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There are problems with the 5.56x45mm NATO round, especially out of short barreled guns — mainly that it’s loud and underpowered compared to what the enemy is using. Many have tried over the years to fix this problem, coming up with wacky calibers like .300 Whisper, 6.8 Rem Special, 6.5mm Grendel, and more recently Wilson Combat’s 6.8mm offering. They all work, but they all have fatal flaws. AAC has come out with a new round that they claim works with existing AR magazines, bolts, bolt carriers, and fixes all the short distance and short barreled problems of the 5.56mm NATO round while still being as quiet as an MP5-SD. Naturally we asked them to put up or shut up, and they invited me out to their Atlanta, Georgia factory to do just that. The put up part, that is.

I had a chance to sit down with Kevin Brittingham, the founder of AAC, and discuss .300 Blackout for a while. And by “a while” I mean it was a 45 minute conversation. The man was a fountain of knowledge, and it just kept pouring. He started with some history.

300 Blackout, which has turned out to be one of the biggest things going for this company, which we’re totally excited about, that was sort of an accident. Just like I value the relationships here, I have a personal relationship with everyone who works here, and with our customers on the military and government side it’s the same way. And those relationships lead to new products. They came to us about a new caliber and that’s where it started. The 300 whisper concept, we need to commercialize it and there are some things we need to fix with it…


[J.D. Jones] maintains a great relationship with a guy who runs one of the military groups that we deal with. Them working together came up with .300 Blackout. They had tried .300 Whisper, and J.D. Jones delivered this group a few samples that worked great. They delivered them 30, 7 of them worked. [Getting .300 BLK to work better] was one of [those] things – getting it SAAMI approved and standards, figuring out how to get the most velocity out of supersonic, making it accurate, making it feed reliably from 30 round mags…

We were working with Bill Wilson somewhat too, and he thought it was a great idea. Then [he] decided ‘oh, it’s not accurate, I’m going to do my own cartridge.’ And he’s doing… Ours is 7.62×35, he went with a longer case – 40. He only cares about supersonic, where our original requirement was it had to be subsonic as well. I was reading yesterday, like you buy these modified – it sort of gets away from the whole beauty of doing this for an AR-15 in my opinion. His you have to modify the magazines, and will only feed like 15 rounds in a 20 round mag or 20 in a 30 round mag…

These were our original requirements for this caliber: Muzzle energy has to equal or exceed the AK-47. .30 Caliber projectile. Use unmodified 30 round magazines to full capacity. Use unmodified AR-15/M-16/M-4 bolt. Gas impingement system. Shoot super and subsonic. And one thing that was nice, but was not a ‘deal killer’, was non-adjustable gas system. Cycle all four ways – subsonic suppressed and unsuppressed, and supersonic suppressed and unsuppressed.

In addition to the original requirements, AAC makes a couple other claims, Specifically, they claim that their .300 BLK gun is as quiet as an MP5-SD, and more accurate to boot.

So let’s take these claims one by one.

First, does it actually work using standard AR-15 magazines, bolts, and the gas impingement system? Well, we saw it in action at NDIA doing just that.

Following that video, Kevin gave me the magazine we were using to keep. I have it right here in my hand as I write this, actually. Let me snap a quick picture…

In the foreground is the magazine being used in the .300 BLK gun in the video, and in the background is a magazine that Magpul sent me recently for the AR-15 magazine testing. The magazines are identical, something that can’t be said for most of the funky “5.56 replacement” rounds. But it gets better.
The reason all the standard AR-15 parts work when using a .300 BLK round is that AAC used 5.56 NATO as the “parent cartridge.” What that means is that you can manufacture brand new .300 BLK brass using spent 5.56 NATO brass simply by trimming off about a third of the case.

In the video above I walk through the steps to do exactly that — turn 5.56 brass into .300 BLK brass — and it takes less than 10 minutes to go over everything. The only additional tools you need are a set of .300 BLK dies. Right now ammunition is a tad expensive ($0.90/round to $1.09/round), and by reloading spent 5.56 into .300 BLK you save about 2/3 of that cost (it runs about $0.20 to $0.30 per round).

Here’s a nice picture showing the whole progression from spent 5.56 case to loaded .300 BLK (the last step is polishing, BTW). It’s actually not a hard process, but if you’re adverse to trimming your own brass then ready made .300 BLK brass can be purchased at a relatively reasonable price from a number of online vendors.

Speaking of ways to get ammo if actual .300 BLK ammo isn’t available, ammunition compatibility is another reason the .300 AAC Blackout round outperforms the competition. The .300 Whisper cartridge has been on the market for a while now and can be found in most gun stores around me, but .300 BLK is still relatively new and ammunition is scarce. Thanks to the higher chamber pressures and larger cartridge of the .300 BLK round the firearms are able to accept and safely fire most .300 Whisper ammunition. I did an Ask Foghorn article about that very question and it goes into some more detail, but .300 Whisper in a .300 BLK gun is generally cool while the opposite is dangerous and will result in malfunctions.

For the rest, we traveled down to AAC’s factory in Georgia for a live fire demonstration and to see how these puppies are put together. Check this out.

I watched John Hollister pull a random AR-15 bolt out of a 5.56 upper and use it in a .300 BLK upper when I shot with him, the bolts are identical. The gas impingement system is in fact present and functioning. From where I’m (very comfortably) sitting it looks like they met their basic design specs.

But what about everything else?

Two major claims remain, specifically that the gun is as quiet as an MP5-SD and that it’s more accurate. Let’s start with the sound suppression, as that was the more fun one to do.

This clip is in the full .300 BLK video, but I pulled it out as it completely answers this question. It’s only about a minute long. Take a peek.

Is it really as quiet as an MP5-SD? No. Myth busted. Nuh-huh.

But it’s damned close.

Standing in front of the guns the difference is pretty easy to spot. The .300 BLK gun “pops” just a touch more than the MP5-SD. Considering that the gun is basically firing an AK round I’d say that’s a damned fine accomplishment. So while it may not be “as quiet” as an MP5-SD, it’s close enough.

Add in some minor improvements, and the gun gets even quieter. I’ve now gotten my own 300 BLK rifle so quiet that the loudest thing you hear is the trigger resetting.

Here’s an interesting fact you can impress your friends with: the barrel of an MP5-SD is actually designed to vent off gas from the 9mm round and turn supersonic ammunition into subsonic ammunition. We were shooting standard, straight out of the box supersonic stuff all day with the 9mm ammo, which means the MP5-SD was actually getting far less muzzle energy than a Glock 19. So when you’re comparing the noise the two guns above are making, remember that the MP5-SD is pushing a 115gr projectile 935 feet per second, and the .300 BLK round is a 220gr behemoth zipping along at 1,010 feet per second. In USPSA speak, that’s a power factor of 109.25 for the MP5-SD and a whopping 222.2 for the .300 BLK. And yet they sound almost equally as quiet.

John also talked about something else. John, for those who don’t know, was in law enforcement for ages. He knows a thing or two about going into dangerous situations and needing to be stealthy. One of the things he kept bringing up was that an MP5-SD might be great for being quiet and maybe taking out a guard dog, a meth dealer who’s been up for three days and is so paranoid that he’s wearing full body armor probably isn’t going to go down to a 9mm round. Thanks to the gas impingement system, instead of suddenly being in need of that M4 that’s conveniently locked in your trunk all you need to do is swap magazines from subsonic to supersonic ammo and you’re able to dispatch Mr. Meth Head with ease. Try doing THAT with an MP5-SD.

In terms of accuracy, the reports are absolutely astounding.

With the 16 inch Model 7 light barrel, we did 10 groups of 5 rounds each with the 155 ammo and it was 0.8 MOA average. That is not a BS 3 shot group picked out of several. No discarded rounds. No flyers. No BS.
-Random guy on a gun forum

For reference, the accuracy of an MP5-SD is approximately 7-8 MoA. That’s “shooting a dog from 5 feet” accurate, not “oh shit that guy on the roof has an AK” accurate. I’ve done some unscientific testing for myself and even at distances most people would consider “long range” it’s a very accurate round.

I may or may not have been sitting in an office when Kevin read off an email confirming that accuracy with an AR and a 9 inch barrel. Not that I’d take his word without seeing the results, but considering the glowing praise this round is getting all over the internet I’m not discounting it either. Rest assured, a request has been placed for a .300 BLK upper to confirm some of this stuff. Along with a silencer. And a T-Shirt. And a trailer hitch. Moving on…

So what about the last part, about being as good if not better than an AK round, and fixing the issues with 5.56x45mm NATO? Luckily I’ve got a chart right here, its name is Paul Revere, and the chart says that if the weather’s clear…

Can do. Can do. The chart says the round can do. And if the chart says the round can do…

Speaking of penetration, there’s a video floating around claiming to show a SLAP .300 BLK round making Swiss Cheese out of a steel plate. Again, I’m not saying I completely believe it until I see some better proof, but the sparks are pretty.

So what’s the final word? What’s my opinion on all this fancy .300 Blackout stuff? My personal opinion is that it’s frankly amazing. By simply changing out your barrel (and JUST the barrel) you get a completely different gun, one with more muzzle energy, able to just about sound like an MP5-SD, and 100% compatible with all of your existing gear. If you own an AR-15 (or even just a short action bolt gun) and you’ve been looking for something that’s easily suppressed, has great terminal ballistics, and is accurate as anything, this is what you want.

.300 AAC Blackout


  • More muzzle energy than 5.56 NATO
  • Able to be suppressed more effectively than 5.56
  • Uses a larger bullet for more damage to target
  • Able to penetrate barriers more effectively
  • Armor piercing and incendiary bullets available (if not completely legally)
  • Supersonic and subsonic ammunition available
  • Swapping between supersonic and subsonic requires no changes to the gun
  • Can be made from 5.56 brass, easy to reload


  • Ammunition is not widely available
  • Ammunition is currently slightly expensive

Overall Rating: * * * * *
I really can’t praise this stuff enough. This is like the chosen cartridge for those wanting to get just a little bit more muzzle energy and a little less noise out of their existing guns. If you’re just running an AR-15 for target shooting and 3-gun 5.56x45mm NATO is probably good enough, but if you’re hunting something, looking for a self defense / SHTF caliber, or needing something that’s quieter than 5.56x45mm NATO ever will be, this is what you need.

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  1. Except ammo availability is not so certain. Until the military adopts it and it’s out there being produced in mass quantities you won’t see wide civilian adoption. This is why 30.06, 308Win, and 223Rem and their military counterparts are such popular cartridges. Same goes for 9mm in handguns.

    If the FBI and thousands of police departments hadn’t adopted 40S&W very few civvies would have pistols chambered in that round. It would be just another oddball cartridge.

    P.S. That’s not to say that .300 Blackout isn’t the bee’s knees, just that it may not be my choice for a rifle round.

    • Remington is mass producing the stuff. According to people in the know, you can expect this stuff on Wal-Mart shelves “soon.” The gun stores by me already carry both supersonic and subsonic varieties.

      Personally, I agree. I’m not replacing my 5.56 guns anytime soon. But I am adding an upper to the collection. And a silencer. And a trailer hitch.

      It’s “novelty” right now, but given some time it may just become mainstream.

    • You won’t see the military adopting this. The wound ballistics of the slower round are just not there. The weight of the ammunition is twice as much as 5.56, for no more ability to kill. The round is slower and so a more pronounced trajectory. This means it is less forgiving when judging distance to target at the longer ranges. Lastly it is at least 100M less range than a 5.56 if you use transonic as the benchmark. All things being equal a 5.56 will go 550M, while a 300BLK will go 400M. No way the military will swap over with all those disadvantages. The most you will see is a few SF units using the sub-sonic capability for silent approach. One or two guys carrying an 300BLK SBR upper in their packs, to swap over for shrinkage ops, but that’s about it. One last thing, the subsonic ammo is three times the weight of standard 5.56!

        • There are not a lot of M14s out in the field. Some are being used in the DMR role, but you wont see platoons wholy re-equipped.

    • .300 BLK and .223 Rem use the same case (more or less), so the real difference is the bullet weight. And the bullet weighs between 123gr and 220 gr for .300 BLK, and only about 55-62 for .223. So it’s about 3 times as heavy as .223. 7.62×39 weighs about the same as .300 BLK, so yeah.

      2.23 times heavier to be specific.

      • I played around with my digital kitchen scales the other night. A Gen2 PMag loaded with 30 rounds of 55gr 5.56 weigh the same as the same magazine loaded with 20 rounds of 220 grain .300 Blackout. (I only had the one box of ammo at the time, too lazy to get 10 more rounds out. Like I said I was just playing around.) An interesting thing I found out, an Aluminum GI mag fully loaded with 55gr 5.56 weighs exactly 1 lb. The loaded PMag’s weight is about .5 oz more. Longer spring/larger follower/denser material, perhaps?

  2. The commonality of most .300 Blackout parts with the existing AR platform gives it a big head-start. Even though it uses standard bolts, lowers, magazines and .308 bullets, however, it’s too bad that handloaders won’t be able to neck up 5.56 brass to roll their own. The expense of the various 6.5 and 6.8 AR caliber ammo, and the decidedly non-bargain price of the bullets, has really hamstrung their sales.

    • You can roll your own from .223 or 556. You chop it off at the shoulder and neck it down (that’s a little over simplistic but you get the idea) and it works. The problem with doing this with the “Whisper” is that you would also have to reaming the neck for it to reliably chamber – not so with the 300BLK. Someone put a LOT of thought into this cartridge.

  3. wacky calibers like .300 Whisper, … They all work, but they all have fatal flaws

    The 300 Whisper and 300 Blackout have small differences in their brass dimensions:
    Blackout 0.004 larger in the neck, 0.018 longer case length and 0.16 longer OAL. Also the Whisper is a wildcat while the Blackout is SAAMI standardized. Apparently those differences make the Blackout the more attractive of the two.

    Would a Blackout chamber accept a Whisper round? How dangerous might that be?

    • Kevin claims that the lack of SAAMI specs mean that Hornaday et. al. can’t load .300 Whisper as hot as they want. So I suppose it would be possible. However, I have this piece of advice for you.


        • @ Nick Leghorn: My lower says – clearly – 5.56 X 45. I hope we all know that “plain vanilla” works in a 5.56 NATO chamber – just not the other way around. (Now sure how many .223-only guns are out there.

          Better advice might be ONLY the ammunition (that’s required to be) stamped on your current barrel.

          When I pin on my .300 Blackout upper on my AR-15, the owner’s manual no longer applies – and the AR-15 lower markings don’t either!

    • The article states .300 whisper can be fired from a .300 blackout firearm, but NOT the other way around due to the blackout having higher pressure in the chamber

    • Assuming a bullet drag coefficient of 0.277 (the value for a 308 Sierra Pro Hunter 125gr bullet) and starting from the published values of 2250 MV for a 125 gr bullet then the GNU Exterior Ballistics Computer gets this result:

      400 yds V 1277 E 453
      500 yds V 1127 E 353 drop 101 in. or 19.29 MOA
      600 yds V 1026 E 292
      700 yds V 955 E 253

      I’ve read an opinion (but unfortunately nothing authoritative) that the max practical range is 600 meters supersonic, 450 meters subsonic.

  4. My dad recently purchased a .300 whisper upper. can you shoot .300 blk in a .300whisper or,did my dad,pick a bad time to buy an upper,

  5. With the only difference between 223 and the 300blk is a different barrel, is there any magazine manufacturers making mags that declare they are for the 300blk? I know the Magpul magazines I have are stamped “5.56×45”. I would love a few to be stamped “300blk” Anyone listening? Maybe a designation color wouldn’t hurt. In mixed company (223 and 330blk), an extra precaution wouldn’t be bad…

    • I was concerned about the same thing, so I use Dark Earth PMags for .300 BLKT and regular black PMags/GI aluminum for 5.56.

  6. I’ve been shooting a 16 inch Pistol gas upper.

    I’ve made 50 cases from 5.56, it’s a slow process. I ended up buying some pre cut LC brass from has some 147 FMJ’s for a good price, so I’ve been loading the Blackout for slightly higher than reloading for 5.56.

    I’m building up a SBR for HD, and when it’s done, I will use the Barnes 110 TTSX, and I’ll try the Remington Pink tip(I think they are 125gr).

    Muzzle blast is lower on the 16 inch Blackout vs a 5.56 with the same length barrel. I’ll have to see if I get excessive blast with a shorter 300 Blackout barrel. In time I’ll pick up a can after the SBR papers come back. My Mags for the Blackout are painted a different color than my 5.56 mags, and it sure is nice not needing new mags.

    The 300 Blackout compliments my 5.56 rifles, I’m glad I have one.

  7. Absolutely great review!! I’m totally sold and chambering all my ARs and AKs in this.. Thanks again for taking the time to help us.

  8. I purchased the “new” S&W M&P 15 300 Whisper for my son’s Christmas. I purchased 4 boxes of Remington AAC 300 Blackout 220g subsonic and one box of Hornady 300 Whisper 110g supersonic. Christmas day we went out to shoot and the gun would not cycle the AAC Blackout without jamming. We changed out the factory 10 round clip and used a new 30 round clip but to no avail. The gun shot the 300 Whisper and cycled perfectly using the Hornady. Ok on my way back to the gun shop and let them look at it.

    • Hey,

      Just FYI, it is extremely dangerous to fire .300 BLK ammunition in a .300 Whisper firearm.

      .300 Whisper was designed to use ammunition with much lower chamber pressures than .300 BLK, and .300 BLK is actually a slightly larger cartridge (which would explain the jamming). I emailed you this information as well, but I wanted to comment so that others would be aware as well. I’m even about to update the article to include a note on interchangeability.

      Good luck and stay safe!

        • k,
          yes they do

          Now Available M&P15 – 300 Whisper®

          Features & Benefits

          Manufactured on the M&P15 modern sporting rifle platform.
          Chambered in .300 Whisper®.
          Will also safely fire .300 AAC Blackout.

  9. This may be totally ignorant, but why .300 AAC when it seems is just imitates 7.62X39 ballistics? Why not just get an AK? I assume it is simply quieter?

    It seems like a lot of fuss when there is already an established platform in the AK.

    • Eric, I don’t know how much you know about the AR-15 and AK-47 platforms, but the reason that having an AR shooting a similar bullet to the AK is so great is because the AR platform is, in terms of accuracy, better than the AK.

      It has a lot to do with the design of the gun itself, as well as the machining going into it (The AR platform rifle will almost always have better grouping than an AK of the same caliber.) If it were an option, people most always prefer a 7.62×39 cartridge in an AR-15 over the standard, undersized .223 round, and the only reasons anyone ever really gets an AK over an AR-15 is because of the fabled reliability, cheaper price (not so cheap anymore) or the larger round. The .300 Blackout round has just made the AK-47’s superior factors obsolete, and all you need is a new barrel for your AR-15 to shoot a better round than the 7.62×39.

      • Two thumbs WAY up for that very precise explanation. The ballistics are the same (very nearly) and the platform is more accurate normally. Supposedly the American made IOINC versions of the AK are shooting MOA!

  10. This will be a new beginning to an ultimate hog buster in the south-east, full-blown with night vision, suppressor and subsonic ammo. (Ground blind approved)

  11. Sweet article man!!! Love the prospect of this new system for greater range and versitility from my AR/M4. Have one question though…I saw at the end of the article that you made the statement that all it would take to shoot this ammo from a standard AR/M4 would be to swap barrels. Its this accurate or will you need to have a special upper as well to handle the energy of this more powerful round? I have been looking all over the internet to see if a 300BLK specific upper must be used to fire the AAC 300 Blackout but cant find a definite answer anywhere. I would be very interested in buying the 300BLK barell if thats all it took to shoot the two different calibers from my standard M4. Especially since Daniel Defense just released its own AAC 300 Blackout DDM4V5. Im sure the barell will be available very soon. Thanks for any info you can give me and keep up the great work spreading awesome news about guns!

    • Hey man,

      ALL you need to swap is the barrel. The recoil isn’t stiff enough to destroy any respectable upper receivers. If your upper is made of balsa wood I would start to worry, but almost anything else is good.

  12. Hey nick,
    I have been trying to get my gun smith to rechamber my 5.56 Styer Aug to 300 aac Blackout. He is not familiar with this round and is worried the chamber pressure would be to much for the guns integrity. I tried to insure him that the round has the same pressure but he wanted me to find out for sure.

    • Carlton,

      You can’t cut a new chamber into your existing 5.56 barrel for this. You will need a completely new barrel with a .30 caliber bore and .300 BLK chamber cut into it.

      I believe that at this moment no one makes a .300 BLK barrel for the Steyer AUG, so sorry but at the moment you’re out of luck.

      That would be one sweet gun, though…


    • Impossible, and dangerous for two reasons. One, the Steyr barrel will still be 5.56 and you shooting a wider bullet down a narrower barrel at 55,000psi will blow it up (and you with it!). Secondly, you would need to push the 300 reamer forward to at least past the shoulders of the 5.56, and re-cut the tendon threads. The thick part of the barrel that contains the pressures ends there and so again, it will blow up. Post us some photos from hospital.

  13. The AR platform may not be perfect but is FAR from being a POS. It is very versatile and adaptable. It is far more accurate than an AK. It is easy to work with and modify for special purposes. There is a good reason why millions of them have been built and used around the world.

    The 300 AAC Blackout is the most exciting addition to the AR family in years. I have started loading the ammo for mine which should be completed soon. There is a place for the 5.56mm version as well as this 7.62mm adaptation. I am loving it.

  14. Looks very sweet indeed, but I’m wondering if possibly something like this round in 6.5 instead of 7.62 might not give higher velocities and better penetration. Mind you, I do realize this is supposed to be an American x39 equivalent. And for that, it seems superb.

  15. It’s because of your article and video that made up my mind to purchase my Noveske 10″ blackout with a 762-SDN-6. Love it. I am curious if they sell the magazines (Emags) that you have with the blackout and AAC stamp on it or is that something they did for themselves. If you could let me know I would greatly appreciate it. Thanks again for the review on the 300 blackout.

    Scott Baker

  16. A friend of mine built a bolt action .300 blackout for my son to deer hunt with. PERFECT round for a small framed 12 yr old. @ 50 yds a 125 gr soft point makes a clean hole in a 3/16 steel plate . My son weighed 65 pounds when he 1st fired this round, virtually no recoil(gun weighs 6 1/2 lbs) & packs 1 hell of a punch when it reaches its destination. I think I need 1 also!!!!!!!!!

  17. Interesting cartridge for an auto loader. My .357 magnum rifle will throw a 125 grain bullet at 2300 fps. Amazingly similar ballistics from a cartridge designed in 1934.

  18. I’m having wet dreams about a rifle in .300 BLK with the StraightJacket® Barrel System modification from I’m thinking it could possibly produce 1/6 MOA (1/2″) 5-round groups @ 300 yds?? I need some money to find out! :/

  19. I am overseas right now but when I return I am building a .300 and I will suppress it and eventually run it on my Colt Class 3 lower. This cartridge is what I have been waiting for, AK ballistics in a modern platform with AR accuracy. The best of both worlds. I predict quite a bit of success for this cartridge.

  20. Reloading – Use bullet manufactures loading data, recommended primer -cci #41 is a hard metal cup for ARs! you should use them but they affect pressure and accuracy. 1st Educate yourself on reloading for signs of over pressure – flattened primers stuck cases in chamber, split necks, case streaching, excessive gas leakage. CHECK Head Space!!!!! with a real gauge.) use correct powder and charge weight for the grain weight bullet used. Use channelure bullets to crimp in case Helps prevent OAL bullet movemt under recoil. Chrono if you have one.
    Dont Guess or follow un tried load data! Under loaded will squibb, Over loaded eats & hammers all!

  21. Just watched loved it, I wasn’t there but I watched the frontal shots and besidesthe first couple of shots before all the oxygen left the suppressor I couldn’t tell the differance. I wish when I bought mine they had this technology because mine sounds like a unsurpressed .22lr. Down the road a little I’m defrenitly getting one The guy that I’ve got three from likes to hold your money I’m still waiting for the theired one for like four years now.

    Guys beware of these dealers that don’t have them on hand and never pay upfront for anything because they have all yr money and don’t care when you get yr stuff.

  22. Good information. But I wish people would quit exaggerating the “weaknesses” of 5.56 Nato. “It refuses to penetrate anything much thicker than a sheet of aluminum.” False. Another guy recently told me, “5.56 ricochets off leaves”, another one I heard, “5.56 won’t even go through a car door.” I would love to see 300 AAC go big. But let me clarify the facts for any poor soul reading this article who is now doubting 5.56 NATO:
    1. 5.56 NATO will easily penetrate 1/4″ steel up to 200 yards and even beyond. 3 months ago saw it penetrate steel just shy of 1/2″.
    2. 5.56 NATO has an incredibly flat trajectory, a fact that was conveniently overlooked in this article. If you like to point your AR-15 at a target hundreds of yards away and not even compensate for drop, the 5.56 NATO is your best friend. No mention here of trajectory or drop at distance. If 300 mimics AK ammo (7.62X39), I’ll make a gross exaggeration like the author of this article and say 300 AAC drops faster than a thrown baseball.

    • to chris reed i was in the military and yes the 5.56 might have a flatter trajectory, but its so light that the wind will blow it around the 7.62 with the 5.56 cut case might make it drop more then the 5.56, but it wont be effected by wind as much. on top of all that the person you hit with it is gonna kw hes been hit unlike the 5.56 round witch i have seen guys continue standing after getting hit 5 times.

      • To Joe. As I said before, I’d love to see this new 300 AAC go big. I see lots of strengths/benefits to this new caliber, including heightened lethality when hits are placed. But, I prefer we speak “The Truth About Guns” and their respective calibers. I don’t appreciate authors spreading exaggerated myths about a caliber’s strengths or its weaknesses. I haven’t served in the military, but I’m confident our government would not send its troops into battle for 49 years straight with a caliber that was grossly ineffective. So, in response:
        1. With all due respect, I’ve also spoken with veterans besides yourself who’ve told me from first-hand experience that 5.56 NATO “put’s em down” or at least “takes fight out of them.” That said, bring on a better cartridge if it’s out there!
        2. 7.62 traveling at 2200 fps WILL drop FAR faster than 5.56 NATO – there’s no “might” about it. Wind drift? I’d like to see true test results.
        3. Most complaints against 5.56 NATO in combat are reported at distances above 300m. Well, this 300 AAC blackout is going to face serious difficulties at distances 300m+ (especially with drop) because it will lose steam and carry slower velocities beyond that distance, which will mitigate many advantages of the larger bullet.
        4. If 300 AAC gets a chance and testing determines it’s all around better than 5.56 NATO and parts availability goes up and ammo prices come down, I’ll jump on board!

      • 5.56 does not get ‘blown around’ more than the 7.62. Wind drift is related to ballistic coefficient. 5.56 has typically higher coefficients than 7.62, meaning you need less windage and elevation to hit the target than a 7.62 (until either cartridge goes transonic and unstable). Being an F Class shooter for a number of years I can tell you that whatever the 308 guys crank on for windage the 223 guys crank on 2/3 less windage in the same conditions. That means 223/5.56 is deflected less in wind and therefore more forgiving, and that means 5.56 is more accurate on a windy day than 7.62.

  23. It really annoys me when cartridge comparisons are done without using the best loads available. For example, the hottest 6.8 SPC loads will push a 110 grain bullet at 2700 fps from a 16″ barrel, generating 1780 ft pounds. The 6.8 is the energy champ (barring the .50 Beowulf, which is really in a separate class). The 5.56 is the velocity king, and carries the least weight for a typical 240 or 360 round combat load out, and has the least amount of bullet drop to roughly 300 yards or so, depending on the load used. The 6.5 Grendel is easily the long distance winner, especially with the Lapua load with a .547 BC.

    Don’t get me wrong, I like the 300. I just get irritated when it is not compared with the best offerings in the other calibers.

  24. i’ve seen the 300 BLK preform well for armor piercing and it’s the or even better than the 5.56/.233 rem. but a flaw i’ve seen is when a 5.56/.233 rem is fired through a tough object like a windshield, the projectile breaks into deadly shards as big as little shards, also the same for a 7.62 but just a little bigger. would the 300 BLK have the same problem as this? and if so, do you think it can out preform the 6.8 rem and the rufles made for it?

  25. My interest in the 300 AAC Blackout is for hunting. Does it have sufficient energy to be a 200 yard whitetail round, or does not need to stay with the 6.8 SPC for deer hunting?

    • 200 yards is about the furthest I would push it for whitetail, but it will work. You’re going to want the 150 grain supersonic variety, and I believe Barnes is now making a specialized bullet just for hunting with 300 BLK. So be on the lookout for ammo using that bullet.

  26. Reloaders will be happy to know that Hornady produces the die set for the 300 AAC, case trimmers are available from multiple sources but the best has been the CTS from Jim Prior that can be used in an electric drill or combined with a coupler that he also produces to use on a 1/2″ shaft motor. Jim’s products can be found on ebay. I’ve found that reloading my own ammunition produced shot groups that were more consistant over factory ammunition even using once fired ammunition, And of course you build exactly what you want at a considerable savings

  27. Muzzle energy is a clumsy indicator of killing ability. I’ve hunted with my Blackout a few times now and it just doesn’t kill as quickly as a 223. We’ve gone back to using 223 for its superior temporary wound cavities that high speed ballistic tips produce. The slower crush-trail left by 300Blackout is more akin to a handgun round. It’s a great little sub-sonic fun-gun though. For serious stuff, stick to the .223.

  28. Respectfully, I have proudly served 8 years military and been active in law enforcement since 1990. I feel through training and experience and being well versed in assessing most of the oddball, wannabe AR15/M16 rounds (like this one) that turn up every few years, it is the opinion of myself and a select group of combat veterans I consulted… This round, though maybe a step in the right direction, is a flash in the pan.

    We also have serious doubts about the credibility of the author. He demonstrates a lack of life and tactical experience … and strikes most of us as an armchair commando.

    This may be an insult but it is also an honest observation based on his demonstrated lack familiarity with the platform he’s reporting on. Basically there is a lack of real credential and it shows.

    We agreed we would have more respect for someone that served some time in a conflict demanding live-fire and familiarity of the weapon under “real” conditions and not simply on a range in a polo shirt and cargo shorts. All he’s missing is a snow-cone.

    Having conferred with folks whom are considered real experts and veterans, we agreed there is simply no foundation on which to build trust. Did you see the conditions in which he was reloading! It is a recipe for either failure or disaster.

    Back to the bullet…

    Of all the potential rounds made to “improve” the performance of the platform at hand, only two ever had a chance to work out, and one was nothing more than a spin on the 30-30. These are the 6.8 Remington, which is really just another name for a 30-30 marketed to make someone enough cash to get a big bonus before customers realize they wasted lots of their folding money.

    And the only REAL contender… The 6.5 GRENDEL.

    The GRENDEL is by far superior in every way to all the other oddballs. It requires minimal changes to the platform and only barely reduces magazine capacity. The cross-sectional density allows it to outperform even the 7.62×51 (.308) out to 1200 yards, and I witnessed reliable hits repeatedly out to just under 1500 yards on a calm day. It has the energy to breach mudblock walls and engine blocks much better than the Blackout, Whisper, and 7.62×51. a few less rounds in the magazine is a fine trade for the confidence of knowing what’s hit, will indeed stay down.

    In a nutshell, if an author wants to write and get respect, try to look professional. Lord knows there are enough idiots trying to pawn crap. It’s just plain dangerous to take the advice of guys like Foghorn… oops, Leghorn


    • What a terrible comment. You spent the first half attacking the guy, complaining about his attire, knowledge, etc. The second half is “heres a better bullet”. You addressed virtually nothing in the article at all. You didn’t contribute anything positive to the discussion at all IMO.

      Thanks, Leghorn, for a great article. You’ve gotten me excited about the round. Sry some people are so butthurt…

    • Phil, I have to agree with John.

      Your expertise and experience make your ballistics assessment valuable, including the opinions of your esteemed LEO colleagues, but your cheap shots at the author were unprofessional and unnecessary. I am sick and tired of the level of incivility I find in Internet forums that serves no useful purpose. You are not the only commenter who disagreed with the author on the value of the .300 AAC round, but you are the only one who made it personal. Please stick to the facts and you will find your comments much more welcome in any forum where you wish to post.

    • Just stick to rating donut shops, Phil. That is the only expertise I see from your end. You, AND your inflated ego pals. Eight whole years in the military, eh? MP? I’ve got underwear with more experience that you.
      Good article, Leghorn. I operate 223REM, 308WIN, and 300BLK and they all have their advantages and disadvantages.

  29. I will open myself for some flak here, but … WTF!!
    This review started as a review of what has got to be the fastest selling, new cartridge, in decades. Now somebody pissed in somebody else’s corn flakes. Yes, some of the author’s comparisons are inflated. Yes, he isn’t in tactical gear while shooting and probably has never fired a round in anger, BUT what the hell does that have to do with the value/utility of this round?
    The 300BLK is not the answer to every problem with the M-16/AR-15/M-4 Stoner platform. (And anyone that says it doesn’t have problems hasn’t used one.)
    What the 300BLK brings, is, a useful upgrade for the M-4. It’s the easiest, fastest, and least expensive solution for some of the M-4’s shortcomings. Everything in current inventory (except ammo and barrels) works with the 300BLK. CQB and normal combat ranges the round excels.
    The round is very efficient, a little powder goes a long way. Loading components are abundant and loading info is becoming easier to find.
    The 6.8 didn’t live up to the hype. 6.5G shines at distance. .223/5.56 was a killer in slower twist barrels(Matty Mattel plastic and twangy recoil spring). The 3ooBLK will live or die on it’s own merits, I say “Kudo’s Silver and AAC”

    • I don’t understand why anyone would trim brass the way you show in the video? With a rotary trimmer that is made for final trim length? When you trim wildcats that have a parent case much longer than the finished cartridge you use a trim die. When the parent case is fully inserted into the trim die the excess brass will protrude from the top of the die. The best way to trim with a trim die is to cut off the case flush with a fine saw or file. When you have the case formed and neck expanded ready to load is the time to use the rotary trimmer to set the final trim length. Lube the case before you insert it in the trim die because it will be a tight fit.

  30. The ACC 300 Blackout can only push a 125 gr bullet to 2100 fps. A 7.62×39 will run 125gr bullets at 2400 fps.
    The ACC 300 Blackout is a quiet weapon but it is not the same as a 7.62×39.
    When the shit hits the fan you will be able to find 7.62×39 ammo just like the 5.56 NATO.

  31. I think most of the negative post are looking at this the wrong way. The .300 blk is a swiss army knife. The ballistics just happen to cross paths at various points with every caliber mentioned. The 6.8 is amazing, but the recoil is a bit more than optimal and you have to squeeze everything the cartridge COULD be into an AR package, which is just a tad too small. Hense LWRC creating a dedicated 6.8 platform. The Grendel is a lovely mid/long range cartridge but is too fat and will soon be surpassed by the 6.8 when the 6.8 is in a 6.8 package…not an AR. The .300 blk isn’t affected as dramatically by barrel length as ALL of the others. IF you want a SHTF or urban warfare/home defense weapon, a .300 blackout is just the ticket. I just bought a 9.7″ and will run it with a supressor. I can then use 208-220gr bullets and be relatively silent for CQ, or toss a clip of 110gr supers and have the same holdover @450 yards as a .223 at 500 yards… what’s not to like? I have a bolt action 7mm-08 for holding down the “Rocky Mountain Fortress” should the unlikely happen.

    • The ACC .300 Blackout is little more than a .30 Carbine with pointed bullets. If you believe it will be any better than the .30 Carbine as a defense weapon then you believe in the propaganda and misinformation posted here.

      • Propoganda?

        I’m talking about ballistics, function, roles, configuration… nothing about hype and propoganda.

        I bought the PWS MK109 for a hosts of reasons… PWS reputation for quality, a gas piston system, a reliable AR platform that can run supersonic and subsonic ammo with no adjustments to the gas system.

        The .300blk ballistics and documented performance with the loads that “I” choose to shoot, are unimpeachable (110 gr TAC-TX Barnes and a 208 gr A-Max).

        I can form brass from one of the most prolific cartridges on the planet. And lastly, unlike most other rounds, the .300blk loses less than 10% of it’s umph when dropping nearly half of it’s barrel length.

        • .30 Carbine 110gr
          Muzz 100 yd 200 yd 300 yd 400 yd
          1990 1567 1236 1035 923

          .300 Blackout 110gr (from Barnes website)
          2350 2070 1810 1574 1369

          So… how again is a .300 Blackout just a “.30 carbine with a pointy tip”?

  32. With double the drop and drift of the 5.56 NATO I think I’ll stick with the 5.56 until I feel the need to go sub sonic and silenced.
    300 Blackout – 110 gr. – 2375 fps – 0.290 B.C.
    Wind Drift ____0______1.5___6.2___14.9___28.1___46.6
    5.56 NATO – 75 gr – 2910 fps – 0.395 B.C.
    Wind Drift____0______0.8____3.3____7.7___14.2___23.2
    (10 mph cross wind)

  33. I was a military sniper. I am a police officer. I’ve never fired a round “in anger.” However, facts are the .223/5.56mm BC ranges from .186-.257. The BC of he .300 BLK is about .366. (Data is not available for all bullet weights).

    BC is simply a way to quantify the tendency of a projectile to overcome air resistance during free flight. The sectional density of the projectile has the greatest effect on BC. The projectiles of .300 BLK are 2.23 times greater than .223/5.56 mm.

    I can think of no scenario where the wind will have less of an effect on a .223/5.56 mm round than a .300 BLK, or any other bullet with a higher BC.

    What you’re really talking about is deflection. Again, the higher the BC the less effect of deflection. Where the incorrect claim that .223/5.56 will ricochet off a leaf has been observed is really deflection. The .300 BLK will beat the .223/5.56 here because there will be less effect of deflection due to physics (newton’s third law). If anyone wants to test this, shoot at a target 300 yards away through tall grass. A blade of grass near your muzzle will cause your bullet to miss your intended target regardless of either caliber.

    If the grass is struck closer to the target, (300 yard target, grass at 275 yards), the .300 BLK will be knocked off course less than than the .223/5.56mm. It is possible that the .223 will miss the the target and the .300 BLK still hit the target. I say possible because bullets still do funny things. In any case, the bullet with the highest BC will be effected least.

    As far as having to adjust for windage less for a .223/5.56 than the .300 BLK , this is either lack or understanding of the differences of sighting systems, a fabrication or a mistake. It can’t happen under the same circumctances.

    • @ “As far as having to adjust for windage less for a .223/5.56 than the .300 BLK , this is either lack or understanding of the differences of sighting systems, a fabrication or a mistake. It can’t happen under the same circumctances.”
      With a comment like this I can see you were never a military sniper.
      Military snipers currently use the MK262 5.56x45mm NATO ammo in the M16 Sniper rifle/designated marksman rifle.
      Cartridge, Caliber 5.56 mm, Special Ball, Long Range, Mk 262 Mod 0/1 (United States): 5.56×45mm 77-grain Open-Tipped Match/Hollow-Point Boat-Tail cartridge. Mod 0 features Sierra Matchking bullet, while Mod 1 features either Nosler or Sierra bullet.

      Muzzle Velocity: 2750 fps
      Ballistic Coefficients
      .372 @ 3000 fps and above
      .362 between 2500 and 3000 fps
      .362 between 1700 and 2500 fps
      .343 @ 1700 fps and below

      • Any real military sniper would understand that velocity plays a major role in drop and drift. You can’t make a 2300 fps round shoot like a 2700 fps round when the Ballistic Coefficients are similar.

  34. “I’m not going to comment on that,” Feinstein told NBC’s David Gregory. “I can tell you he is going have a bill to lead on, because it’s a first-day bill I’m going to introduce in the Senate and the same bill will be introduced in the House, a bill to ban assault weapons. It will ban the sale, the transfer, the importation, and the possession — not retroactively, but prospectively. And it will ban the same for big clips, drums or strips of more than 10 bullets.

    • The arguement has never been about controlling guns, but gun ownership. No law resrticting gun ownership in ANY country has resulted in lessening violence or murder. Mrs. Feinstein knows that. Anyone that has seen Jerry Miculek shoot 12 rounds in three seconds from a 6 shot revolver knows that limiting the capacity of the weapon has little to do with it’s lethality. The reason for restricting firearms (in any way) is for the express purpose of reducing your right, to defend yourself, to a priviledge granted by the government. Once that right has been accepted as a priviledge, then the goverment can simply revoke it. Our only hope is that individual states refuse to abide by whatever restriction the government imposes, similar to how several states have refused to set up health exhanges for Obamacare. I’m not a conspiacy theorist by any stretch of the imagination. Because, if there is a “consipracy” it is by nature, not design. I wonder if Americans still have the will to say, “enough”, and stand up collectively to the government and the ignorance of those who fear a weapon more than the evildoers that couldn’t care less about assault bans, restricting capacity, or even legal ownership.

  35. Just got the 300 AAC Blackout !I bought six boxes Remington 115 gr and Two boxes of Remington125 gr. The 115gr jamed about every 4 to 6 shots?thats wrong! Later I changed to the 125 gr and the gun shot perfect ?whats the problem and do you think thr Dealer will take back the 115gr for the 125 gr.?

    • When you say “jammed”… did it stovepipe, doublefeed, not cycle fully, fail to eject… ?

      Is there an adjustment on the gas block for supersonic/subsonic etc… ?

    • When I shoot the 115gr the shells would double up in the chamber un fired. I hope this helps a little about the problem .Later I will be doing my owe reloaded .I hope by putting a hotter charge in will end The problem?You say there is a adjustment on the gas block ! I have on idea were this would be thanks any way! Les

  36. Most of the negative comments i see towards this round are based on 2 things that SHOULDNT be compared, and one misconception…as i see it.

    The 300aac shouldnt be looked at as a replacement for the .223/5.56 because it isnt, and wasnt supposed to be a bandaid for a varmint cal.

    People compare this to 7.62×39, which drags all the ak fans out to rip on the ar platform.

    The misconception: This is a round to be used beyond 300 yards. I wouldnt shoot this at any game beyond 200 but for target shooting sure.

    The LIGHT for caliber bullets used in this cartridge have ballistic coefficients that stink compared to other .30 cal stuff and the .223 is always going to do better with the longer/narrower bullet. Im going to work on a 7mm version of this for fun and see if i can get a barrel cut for me because the BC on 7mm typically are higher than most other.

    REALLY this cartridge should be looked at from the CQB standpoint for the inlisted or mall ninjas (tac-tards). The package should be compared agains what is typically pistol cal carbines and “pistols” that really cannot compare in regards to pressures and velocites.

    HAVING RANTED, i really like the cartridge. Its fun, uses very litte powder, doesnt beat your gun up badly like another awesome caliber 450 bushmaster.

    Look at this caliber on its own merits, and if you dont have the money to fork out for an upper or barrel dont bother posting. People who have shot the damn thing should be the ones talking. I found that i have no drop to speak of @ 200 yards with a 100yd zero. My ccmg 16″ carbine gas system wouldnt cycle subsonics on the first range day. A captured buffer spring system with varying springs for different loads will be tried and chrono data will be up.

    If you have the $$$ i dont think you can be too unhappy with this cartridge, and if you can work on your guns to tune them it will be a pleasure. Hope this helps, with lots of opinion mixed in.

  37. The only problem I have with the 300 Whisper/300ACC is changeling cal from a 115cal to a 125 cal and I see the same problem with RJS ,DEC 28 th
    By the way the 300aac blackout has no comparison with the 223 .The 300aac blackout only has the range of 300ft with any accery!

  38. Ok, I’m new to the AR and not educated at all and will never claim to be an expert. However, due to recent events I have order two rifles. One is the CQB – Patrolman’s Carbine – .300 BLACKOUT and the other is Designated Marksman Rifle in .223/5.56.
    I now relize that I could have only purchased one and purchased a barrel for the .300 BLK. But I have two boys that will get one each one of these days.
    Could use some good advise as to what I should be doing to prepare for the arrival of the rifles. Going to the gun show tomorrow and need to know what I should be purchasing to support the rifles. Ammo, mags, accessaries etc.

  39. Lets be honest…
    6.8 is a cqb only round for a reason. and expends all energy on barriers worse then 5.56 does.

    6.5 is prob the future if cost come down. Its really just a +p version of a 5.56 (in basic design)

    .300 acc is as close as you will get to the infamous .357 from this platform question thats always asked. honestly it lacks the power to knock anything down past 200m as does the 7.62×39.

    Until the 6.5 becomes a cheaper and more supported platform….

    if i was to change out the upper for a diff round right now for cqb or hunting as would be the only POS for the 300 or 6.8 round i would go to the .450 or .50. Out to the “USABLE” 200m effectiveness range these hit way way harder and dont destroy the needed 5.56 brass. 10rnd mags still leave me feeling fuzzy cause if these drop a 6-800lb animal dead in its tracks IT WILL destroy a 200lb target.

    To you reloaders cutting these down… How cost effective will it be when 5.56 brass keeps going up because you keep destroying the brass? This will never be a viable option real world although it does “sound” cool.

    Last note…. To the effectiveness of the 5.56…. To anyone who has actually used and/or research other then hearsay and rumours… this round is a purpose built human killing machine. It has the perfect kill/damage potential due to its design on a human target. 6-10″ of penetration is your optimum kill zone. Thats where the 5.56 is purposely designed to create the most damage. This is the zone where the round frags or tumbles depending on bullet type. The frags are designed to create tissue damage ahead or the remaining round. This in creates more vascular damage which other then spinal cord separation is the only way to stop any living thing. The boat tail design tumbles in the kill zone and effectively creates over a 1′ perm cavity. Both create shock cavities the size of 2 soft balls in the optimum zone. Make no mistake about it. This is the only round that has been specifically designed for combat killing ever. Realistically the only area when the 5.56 is weak in design is carrying energy to a target through barriers. (This is actually the real stories you hear downing the 5.56 from operator use. The second being oh it has no knockdown power… True the round “sometimes” looses its ability to frag or tumble PAST 300m. Ok sooo. The average engagement distance is 50-75m ) This is why the 6.5 will eventually be used. It acts the exact same in body and is a barrier punching machine with better long range potential then the 308. It will be the final one size fits all round that will further simplify combat loadouts.

    Just my in site on real use and designs from someone involved in both aspects of AR platforms.

    • Perhaps you should review the ballistics table I posted earlier. While it may be true that a 220 gr subsonic round approximates some magnum pistol rounds, a 110 – 125 gr yields a completely different story. The blackout is minimally affected by cutting the barrel down even to 7″, whereas the 223 becomes all but useless below 14.7″. Of all the calibers you mentioned, only the 223 and 300 have manageable recoil for cab. In an SBR, the 300 shines. And, if the situation suddenly calls for a 300yd + shot, there is no need to grab another weapon since the 300 will carry more energy past 500yds than the 223. I own a 300 in 10″ and am building a 16″ 223. I have zero issues with any calibers mentioned. I just think that the 300 has the greatest versatility.

    • average engagements in current combat environments take place past 300 meters in Afghanistan. I don’t know where your getting your stats but they NEVER took place THAT close in either of the two wars we’ve been fighting in the past ten years and ANY veteran could tell you that.

  40. @ “the 300 will carry more energy past 500yds than the 223”

    That like most of what is posted here is just bullshit!
    When you take your selected top performing 300 Blackout and compare it to modern 77gr 5.56 NATO combat ammo then the 5.56 NATO exceeds the energy of the 300 Blackout at any range, and the longer the yardage the greater the difference in favor of the 5.56 NATO.
    If you want a subsonic rifle then use your 300 Blackout! If you want a rifle for combat use the 5.56 NATO! Just because the 300 Blackout sux less in SBR’s doesn’t make it into the miracle caliber you claim. This is just a new version of a 300 Whisper, and you will never see these same claims made by J.D. Jones! The bullet drop and wind drift numbers must also be considered when you use this for a long range weapon. You will never come close to the drop and drift of the 5.56 NATO with the 300 Blackout.

  41. Interesting Kirk,

    In researching exactly what you proposed, I found this:

    This is a brief energy chart of 5.56 77gr Nato alongside the 300blk 110gr Barnes:
    100yds 1070/1094 — 200yds 880/920—- 300yds 715/770

    Perhaps the 556 catches up with the 300blk in a couple hundred yards. I’m not sure… the Barnes chart I found only went up to 300 yards.

    However, even from a cursory glance, it would appear that the “bullshit” is flying from your corner as much as anyones. To be honest, you made the best case for the 300 blk of anyone on this board. The 556 sux as a SBR, and the 300blk is barely affected by cutting the barrel down from 16 to 7 inches.
    I can carry a “single” SBR weapon with a suppressor… I can load a mag of 208gr or 220gr and run “silenced” OR… IN THE VERY SAME WEAPON… pop in a mag of 110gr and and shoot as accurately AND with as much (or more) energy (at least up to 300 yards according to the charts) as your beloved Nato round. And I won’t even mention the whole barrier debate ….

    The 5.56 Nato does great in a few circumstances and absolutely sux in most others. The 300 blk is (as I said before) the Swiss Army Knife of combat rounds. And we are in the infancy of the round. Look at how the 6.8 has come along in just the past year.

    If you don’t like what the charts say, then you should take Barnes, Hornady, Nosler to task and prove them wrong. I’ve seen enough ballistics testing from reloaders on 300blackoutforum to give me confidence that the data is indeed accurate, and not some fearful and emotional ranting and raving.

    • P.S. Kirk, Perhaps you missed this part of the paper you linked:

      “At the end of the day, what can we say about the 5.56 x 45 mm NATO cartridge? Is it adequate for combat? Arguably, yes. Are there better cartridges for this purpose? Undeniably. Equally undeniable is that the military ball loads are non-ideal.”

  42. In the real world the vast majority of AR owners can’t own a SBR. The AR’s that are commonly owned have a 16 inch minimum barrel length. You like to cherry pick ballistics to reinforce your argument! You have no idea if your ballistic tables are real or not. The chart posted here claims a 300 Blackout can run 123gr bullets at 2315fps from a 16 inch barrel but if you check with that is not the case. The bullet weights that archived speeds in a 16 inch barrel above 2300fps were only the 110gr and 115gr. In the real world the 5.56 NATO will shoot 77 gr Sierra Match King’s @ 2778 fps from a 16 inch barrel. The ballistics chart here shows a reduced speed of 2938fps in a 16 inch barrel for the 62 gr FMJ-BT (M855 / SS109 Ball). In the real world the velocity for a 16 inch barrel with 62 gr FMJ-BT (M855 / SS109 Ball) is 3078 fps. The Barnes VOR-TX ammunition Caliber: 300 AAC Blackout Bullet Weight: 110 Grains has Ballistics Information: Muzzle Velocity: 2350 fps Muzzle Energy: 1349 ft lbs. The inflated energy numbers here claim that the 300 AAC Blackout has 1462 ft lbs of muzzle energy. You use inflated ballistic numbers for the 300 AAC Blackout on a chart with deflated numbers for the other calibers listed. The 77 gr Sierra Match King (Buffalo Bore Sniper) in a 16 inch barrel gives 2778 fps and 1319 ft lbs of muzzle energy. Your deflated numbers here show only 1188 ft lbs for the 5.56 NATO in a 16 inch barrel. So what we really get from a 16 inch AR is 1319 ft lbs for 5.56 NATO and 1349 ft lbs for 300 AAC Blackout. With a drop of 428fps in muzzle velocity for the 300 AAC Blackout I don’t see how you can claim it would give better long range performance than the 5.56 NATO. The excessive drop and wind drift would make it very difficult to hit anything at long range with the 300 AAC Blackout.

  43. I can’t count the number of times I have posted (specifically to you), that the charts are for the 110gr Barnes, … NOT 123gr.

    When I speak of the versatility with regard to barrel length, you obfuscate with “In the real world the vast majority of AR owners can’t own a SBR. ” I’m speaking of the performance of the round, not the intricasies of the law. I own an SBR btw.

    You make the comment that the 300 blackout is nothing more than a 30-30. I posted the chart from Barnes that clearly shows a 30% improvement over the 30-30, and your response is that, “well I can see that it is a little better”. Thats like saying a 338 Lapua Magnum is “a little better” than a 30-06.

    I have never contended that the 223 isn’t a viable option. It is a wonderful cartridge. However, it has some severe limitations… limitations that I feel are in part corrected by the 300 Blackout. I don’t have to rely on one optimal round. Everything the 300 blackout feeds performs well. And the same weapon can go subsonic and supersonic with only a change of the round.

    For my money the 300 blackout is as close to a “one-gun” solution as it gets. For virtually any scenario from home defense, to whitetail and hogs, to urban combat, I cant envision a better choice. If I need a 1000 yard shot, I’ll use my 7mm-08.

    And speaking of hunting, most states where I have lived do not allow .22 for hunting anything but small game.

    Frankly, I doubt that anyone is even paying attention to this thread anymore. It has turned into a pissing match about things beyond the intent. I hope that you enjoy your .223 as much as I enjoy owning my 300.

  44. The 300AAC should not be compared to the 5.56 or the 7.62×39, it is more of a SMG round. I would use it for suppresed CQC work. The 230-250gr hard cast lead alloy @ 1100 fps would be compared to the MP5 or UMP. This is teh area where this round shines. All the same parts as the AR/M4 family except the BBL. Carry an upper with a can and a hundred rounds like we used to with the MP5SD.

  45. I cannot see the difference between the AAC Blackout and the 300 whisper. The 300 whisper has been bouncing around for the last 20 years or so and has never been pushed as hard as a few companies are trying to push the AAC Blackout. I seriously doubt that the military will adopt this cartridge to replace the 5.56 for all the major armed forces in the US. It was hard enough to get NATO to accept the 5.56, and now a couple of gun companies want to replace that. I cannot argue that the 5.56 is everything a soldier could ask for in a military cartridge, but everything out there has it’s limitations, including the AAC Blackout. This cartridge just is not an over the top improvement over what they already have, and comparing it to a 9MM pistol caliber sub gun is not a good way to get people interested unless they think 9MM pistol power is what they want in a battle rifle.

  46. Really glad to have found this site. I just bought a Daniel Defense 300 Blackout upper and I can’t wait to go shoot it! No ammo at the time of purchase which was a bummer. Hoping that changes eventually. All I know is I wanted something with more knockdown power than my .556 and quieter is always better. Thank you for everyone’s posts & feedback in either direction. Wanted the socom .458 but this came along first and I’m sure I’ll enjoy it within it’s purpose. Thanks again

    • That’s what I was thinking reading some of the posts about military adoption of the round.

      I still want one. It would be perfect for Texas deer hunting. Nobody should have to shoot from much more than 100 yards here.

  47. I love both calibers and have been shooting .223 since 1969 in service duty. I know personally the M16 was a very handy weapon for quick burst and very low recoil. As I have built many different loads for the .223 from target to hunting, the 223 has it’s very purpose for both and limitations as with most any caliber. The .300 is fun to shoot, very accurate with Super and Subsonic loads. It took much more work to develope a number of workable loads for the .300 but I do enjoy the wider range of fun and terminal ballistics when compared to the .223. With a suppressor mounted it becomes a weapon of choice over the .223 for me but I’ve only been shooting rifles 55 years and loading, developing ammo for 45 so that is only my personal opinion. Thanks for any helpful input you might have. Safety notice, do not use the max load listed for accurate powder for the cup is so excessive it will blow primers, expand cases beyond safety limits, and flatten brass. Never had so much trouble building a cartridge using manufacturers data. Seating depth is very critical with this one as well. Happy shooting friends!

  48. I find it interesting that the author took aim at some of the most revolutionary innovations in the shooting field in more than ten years. The 6.8mm SPC is currently being used by special forces and 6.5mm is being seriously considered for mass adoption (in consideration with the latter). I have a 300 blackout from Faxon and it is a neat round but it doesn’t have a whisper’s chance at a metallica’s concert or being adopted as a choice round because of it’s lack of performance characteristics at long range. The 6.8 SPC was developed by the special forces community (need I say more…) and Remmington while the 6.5 Grendel is a close (if not neck-and-neck) contender. I am not going to go as far as quote round velocity at given distances or kenitic energy on target but the military isn’t interested and that should really tell us all we need to know. They only considered 300 AAC Blackout for surpressed missions. That’s like less than 1% of all missions undertaken – this round is interesting but it doesn’t have the range or the velocity (at distances) to justify the massive change in it would take in changing all of the US military (not to say the rest of the NATO) over to this round. The 6.8mm SPC is still being used (USED) by special forces and elements with the SOCOM community to this day. Operators are also talking about 6.5 Grendel (with it’s favorable and, in some cases, superior applications) as the “next thing.” What I’ve never heard of is any (ANY) interest in the 300 blackout because of the lack of punch – despite the larger grain. A killing round needs to be perfectly balanced between velocity, accuracy and kenetic energy. The major problem with the current NATO round is simple: while it is fast and accurate, it lacks “killing power,” – or the ability to end the participation of an individual once they’ve been hit by that round on the battlefield. For instance, battlefield medics have been able to save the lives of insurgents who’ve been shot more than ten times with 5.56mm (including some instances where “vitals” have been hit in the process). The Pentagon is shopping around for a bullet which will reliably do enough damage to put an enemy down permenantly with a first time hit to the torso or main appendage (upper arm or upper leg) 80% of the time. 5.56mm was origionally intended as an airforce security weapon (where it made sense because the guards were going to be fighting and defending a US base – probably inside the US or Europe). The last thing the direct impengement system of the m-16/m-4 carbine was intended for was the middle east or jungles of Vietnam (despite the fact that I can still find US government films stating otherwise…). The two new innovations we’ve seen in the developement of military weapons on the civilian side is the fusion of the AK’s gas piston system into the M-4’s frame and the adoption of new calibre’s. 300 AAC blackout is not going to be the new round for NATO. Sure, we can still use all the old mags, sure we can retain the bullet count (or near to it) with all the old mags but the round itself can’t achieve the objective. It’s not fast enough and dosen’t have the kenetic energy at long ranges (where the majority of combat takes place in Afghanistan – the 6.8mm SPC is PROVING itself to be a MUCH desired candidate for that type of combat, while 6.5mm Grendel is a consideration for some of the same tasks (but not taken into the field yet because an “A” team’s operator needs to be able to share their ammo with another – you’d need two shooters with 6.5mm Grendel and that opprotunity hasn’t occured to the knowledge of this author)). If they got 300 blackout above 2000 FPS at 300 meters, the military would be more than interested (because it would far EXCEED the performance of the 5.56mm but that doesn’t seem possible even considering the most powerful power forms now coming out on the market) but it’s problem is the casing size is too small to produce the pressure necessary to maintain that velocity at that distance. Simply put, in the mind of this “gun nut,” it’s too much bullet with too little power behind it. If I am right – what’s the point? Even if it a “superb supressed weapon cartrige.” The military (and I) am only interested in an all-around preformer. Very, very few people could find themselves in a situation where they could say that the 300 blackout saved their lives and they would have been dead if they had been using 5.56mm, 6.5mm Grendel, 6.8mm SPC or .308. In my view, the latter four are more tempered for combat, the 300 aac Blackout is really only intended for hunting small(er) game like cayotes, deer and mountain lion. If you want a SHTF – look else where because you won’t find one more source for ammo after the lights go out. Keep that in mind – many more have private presses for 5.56, 6.5 Grendel, 6.8 mm SPC and .308.

  49. First let me say I lean more to the traditional side of things in general.
    With a .22 LR, .223 & .30-06 a person can do anything that needs done in North America. Now I will go on and say that when you include the large brown/grizzly bears, the .30-06 would not be my first choice, however I have done it. That said, I’m not a fan of every new “high speed low drag” whatever round that comes out each year. BUT, a LOT of people have been looking for a round that is better than the .223/5.56 for personal defense & medium game hunting. Of course the 7.62X39 has been around for a long time and is a good round, but most guns it is chambered in leave us wishing for more accuracy! Now, someone has come up with the .300 Blackout, which is more powerful than the 7.62X39, in a platfrorm that is almost always more accurate and all a person has to do is change a barrel on their AR-15 and EVERYTHING else stays the same. It sounds like the least amount of $$ & equipment change to gain a lot over the 223/5.56. I will give it to the “nay sayers”, the .300 Blackout ammo is more expensive than either .223/5/56 & 7.62X39, but you are getting better performance.
    Bottom line, I’m not rushing out to buy one………yet. I’ll continue to monitor the situation as I use my .22 LR, .223 & .30-06 to do what needs done (when using a rifle). Handguns & calibers are a whole other discussion………

    • No the.300 Blackout is not more powerful than the 7.62X39. The misinformation posted here would lead you to believe that falsehood.

  50. You call the .300 Whisper “wacky,” but endorse the .300 Blackout… They are nearly identical. If anything AAC copied the 300 Whisper, changing it just enough to not deal with patent issues, then submitted it to SAAMI so it’s a standard cartridge instead of a wildcat. They are so close that they are interchangeable. Even S&W in their M&P15 shows it as .300 Whisper/.300 Blackout.

    If anything a .270-.280 (6.5 tp 6.8) round would be the ideal… Three calibers, one American and two British were looked at and rejected between both world wars. The .276 Pederson, then the British 6.5 and a 6.8. Then the 6.8 SPC and 6.5 Grendel. There seems to be something about those rounds that keeps them showing up over and over again. Even the 7mm AR would be a better general use round than the .300. It’s a 200 meter cartridge at the very most with light fast moving ammo. It’s niche is shooting suppressed with a 200+ grain bullet.

  51. I’m looking at getting a .300BLK upper for my AR platform, but I’m a little concerned about the availability of the .300 AAC Blackout rounds. Can this barrel fire anything else besides the .300 Whisper rounds?

    • Sarah, the chamber of the 300 BLK and 300 Whisper barrels are essentially the same, so they can chamber the same ammunition, but they cannot chamber any other ammunition, like you can’t use a .308 Win in a 30-06 or a 270 in a 7mm-08.

      Hornady loading data is the same for both 300BLK and 300 Whisper. They state the difference between the two rifles amounts to a 0.015 in deeper throat in the 300BLK, something you’d need precision equipment for to tell the difference. As a matter of fact, I’m using Hornady 300 Whisper brass to load for my 300 BLK, with absolutely no issues, shooting Sierra 125 HP Match King and 155 HPBT Match King bullets in a 16″ barrel. My rifle is as accurate at 175-200 yds as my .308 Win is at 300-350 yds with similar weight bullets. I don’t ask the Blackout to perform as well at long ranges, that’s not what it was intended for, but I’d sure hate to be on the receiving end of a 200 grain bullet past 200 yards from one.

  52. For anyone who is wanting to reload or is currently reloading 300 Blackout go check out GSI International. We have a developed a great way to cut off the neck of your 223 casings. Our kit comes with a new tool head for your 550 or 650 Dillon reloading machine and 2 trim dies.

  53. My oldest son is sold on the .300 BLK.I’m not as enthusiastic though.I have my Ar15’s,..and in 30cal. I will just hang with my .308 bolt’s and AR10 until the .300 BLK been around awhile.

  54. Lets get down to brass tax! Which one of the posters here complaining about this round are going off to war and bring along his/her own gun? There is a place for every round. I am a part time hunting guide. I guide hunts at my Wyoming ranch where there are hundreds of thousands of open prairie acres to shoot. Few, at best, hunters and shooters can effectively shoot out beyond 300 to 500 yards, in the real world, not at a range shooting paper. This round fills a nice gap. The 5.56/.223 round is not a humane hunting round for hunting big game, Within 300 yards this round would be. The 5.56/.223 was never intended to be a “killing round”, but rather a “wounding round”, when military statisticians determined that killing an enemy troop only removed one man from the field where wounding an enemy tied up 10 more in support. So any claims of the 5.56/.223 round’s killing potential is immaterial. There is a place for any round, but, if you are all going to sit back and tell me that tiny little glorified .22 round is the round of choice for long range shooting, I would have to say your barking where the trees prevent you from shooting far enough to know. Out in the open prairie we can watch the flight of every round we fire, muzzle to target. I would never select either the 5.56/.223 round or the 300 Blackout for killing shots beyond 300 to 400 yards. (There are far better long range guns and rounds to select for this application.)I imagine that I could find this round useful to hunt white tail and prong horn. I would use it in the same way as I would use a 30/30. For that reason I put together a 300 blackout/AR. Is it the perfect round? No, but neither is the AR the perfect gun.

  55. Short and Sweet cartridge…….however until the 300BLK is adopted by a viable law enforcement service or the U S Military and the commercial ammo becomes more reasonable, I’ll stick with my 5.56 / .223 As far as penetration my “Tap Barrier” ammo goes right through refrigerators, car doors , 3 inch fence posts ….. and my 77gr. “Buffalo Bore Sniper” ammo will reach out and pound accurately at 600 yds. Just my opinion.

  56. .300 blackout is still the same price as 308 and still doesn’t have the same ballistics. So I went 308 on my ar with the new current 308 ar’s made lighter and short to long ranges are good even suppressor ready if desired. Also seen cases of certain 5.56/.223 shell cases that are out of spec for 300 black out when relodreloaded

  57. I was skimming through old Jeff Cooper’s Commentaries and found the following mention in his first column, Vol. 1, No. 1 June 1993:
    J.D. Jones, the prominent advocate of pistol hunting, dropped by the other day to show us a most curious ballistic development. He has taken the 223 case, blown it out to 30 caliber and installed a match bullet inside which takes up practically the entire case. A pinch of the proper powder pushes this bullet out the muzzle at subsonic velocities, thus permitting silent fire. There have been similar endeavors in the past, one of which I developed myself, but this one is unusual in that it is adapted to the M16 rifle, hence the finished cartridge will work through the magazine system of the M16.

    Now this loading was for subsonic velocities for suppressed fire, but i found it interesting that a 300 blackout type of cartridge was made by J.D. Jones all the way back in 1993!

  58. Most critics and doubters are the ones that alredy own a 5.56 or AK or 6.8 system. And that’s natural, heck the entire military is exactly like that. But if one was a brand new AR buyer and had a choice of their very first AR today…. going 300 BLK is a no brainer given all the current ballistics data, actual reviews, and adoption rate out there. Just so many extra benefits of 300 BLK (identical equipment, 4 mode operation, NFA friendly) that easily negate any of the ballistic nit-picking going on. Forest from the trees kinda thing…..

  59. My 300 Blackout AR rifles are now my goto rifles and all I use is Ozark Ordnance 300 Blackout. I’ve gone through thousands of their rounds without fail. 147/150 FMJs, 125 SST Supers, and 208 A-Max Subs. Check them out.

  60. Umm, wasnt this round invented in 1943 as the 7.62×39? Why go to all the bother of this when you can go AK?

  61. Sorry if a dumb question but can you shoot 5.56 through your .300 blackout barrel?

    And has .300 ammo gotten easier to find since this excellent article was written?

  62. Sorry if a dumb question but can you shoot 5.56 through your .300 blackout barrel?

    And has .300 ammo gotten easier to find since this excellent article was written?

  63. Hey bud, great article. What was your source for that Paul Revere chart? I’m deciding on parts for a 300 AAC build and wanted to compare velocities of a range of ammo with different barrel lengths. Harder to find on the internet than you might imagine… Thanks.

  64. Wow, someone has been drinking the 300 BLK koolaid! When I read the word “whacky” when referring to 6,8 SPC, I knew this was going to be a personal/paid endorsement for the authors pet cartridge.
    Have you not read ANY technical information on those “whacky” cartridges?


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