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The nice thing about the AR-15 platform is that with the push of a couple pins you can change the entire ballistic profile. New barrel lengths, new twist rate, even new calibers, delivered straight to your front door without all that mucking about at gun stores. After my visit to AAC’s firearms wonderland, I was bitten by the .300 BLK bug. The silencer is still months away from being mine (the gun store lets me come visit it every once in a while), but that doesn’t mean I can’t play with the upper in the meantime. Despite ammo being rare as hen’s teeth around me (and none too cheap either) I put a couple hundred rounds through it the other day and I’ve formed an opinion. I think.

First and foremost, if you haven’t heard about .300 BLK or don’t know a lot about it I’ve written a pretty comprehensive review of the .300 AAC Blackout round that you can read and educate yourself. It’s a remarkable cartridge that is just starting to take off as a law enforcement, home defense and hunting replacement for 5.56 NATO.

The real benefit of the .300 BLK round is in the shorter setups. With the 9 inch setup you’ve got a weapon that, silencer included, is as short and (almost) as quiet as an MP5 but delivers a harder punch and a more accurate shot. Which is great for police and military, but as a civilian it’s not a dealbreaker to have a 16 inch barrel. In fact, I prefer the longer barrel for more accuracy and a quieter weapon.

Yes, I said quieter weapon. A longer barrel allows the powder in the round to be more efficiently burned which decreases the report of the rifle. The .300 BLK cartridge was designed with stubby barrels in mind, so the powder is optimized to be completely burned up around the 16″ mark. Compared to the 5.56mm NATO cartridge (which is optimized for a 20 inch barrel) the report alone is much softer sans can from a 16″ barrel, which will eventually translate into a quieter weapon with the silencer attached. Once my paperwork has cleared. Eventually. Next year probably. If the sheriff gets off his ass. I’m getting depressed, let’s move on…

The upper comes with a full auto bolt carrier. Which makes sense, considering that the clientele that AAC is catering to typically have access to full auto everything they want. For us lowly commercial purchasers it’s less likely that we’ll be needing that feature, but I’ve always been a fan of the heavier bolt carrier — it adds some weight to the bolt to slow the cyclic rate down a tad, and increases the structural integrity of the part. And, because it’s a .300 BLK upper, everything on the bolt is completely interchangeable with your 5.56mm NATO rifle and replacement parts. In fact, everything except the barrel is completely interchangeable with 5.56mm NATO kit.

The rail system is a Knight’s Armament Co. rifle length URX rail system, which measures a touch over 12 inches. The upper has a carbine gas system, which places the gas block well under the handguards. Some may speculate that placing one’s hand directly over that section of rail would be uncomfortable but I didn’t have any issues with heat or gasses.

The handguards only come with the full length top rail and some short side and bottom rails at the end, and that’s about it. I was expecting to hate the oddly shaped handguards, but on the range they aren’t noticeably uncomfortable. The upper ships with small rails at the end and some rail covers on them so you can “Costa Grip” to your heart’s extent, but there’s nowhere on this handguard that you won’t find a good grip. The upper can be expanded with additional rail segments if you really feel the need.

The barrel is completely free floated in the handguards for improved accuracy, and it also helps keep the handguards cool. There’s a heat shield bolted to the bottom of the handguards that extends out to the gas block but the rest of the barrel is completely exposed. This might get a bit uncomfortable with high rates of fire, as I have fond memories of the handguards of John Hollister’s 9 inch .300 BLK gun starting to burn me after a few hundred rounds. But with the current price of .300 BLK ammo I don’t see that being a problem anytime soon.

That free floated barrel gives the upper its remarkable accuracy. This video shows me singing an IPSC steel plate at 250 yards with boring regularity using this upper. I haven’t done any “official” groupings yet but even with iron sights and a red dot this thing is miles better than my bolt guns. Whether that says something about the quality of this upper more than it says something about the quality of my bolt guns is another matter…

Because this is from AAC it comes set up from the factory to take their quick attach 7.62 silencers using the Blackout flash hider. Which is slightly maddening. Like the Vortex flash hider that came on my Noveske upper, it emits a noticeable “ping” every time the bolt is closed or the trigger is pulled. Just like a tuning fork being struck. Most people don’t mind it, but to me it’s absolutely infuriating. It’s a Gb, trust me. I just spent the last hour with my violin and a rock hammer figuring it out. AAC makes something called the “Brakeout” that’s a muzzle brake slash flash hider that doesn’t ping and still mounts their cans, but it’s extra. Being a cheap bastard I think I’ll live with the ping.

Looking at that flash hider I can still see where my silencer scraped off some of the finish when I mounted it on my upper last week. Damnit, now I’m thinking about my silencer again, all alone in that dark gun safe. Don’t worry boy, you’ll be home soon. OK, we have to wrap this up before I start getting depressed again…

AAC .300 BLK 16″ Complete Upper

Caliber: .300 AAC Blackout
Barrel: 16″
MSRP: $1,000

Ratings (Out of Five Stars)
All ratings are relative to other similar products (in this case 16″ uppers).

Accuracy: * * * * *
At 50 yards this thing wasn’t floating very far outside the 10 ring. Considering the 10 ring is only slightly larger than the bullets I was firing that’s good enough for me. I’m going to stretch its legs soon, I’ll update this review if it drops below expectations.

Ergonomics: * * * * *
Doing the “Costa grip” feels natural, but holding it anywhere on the handguards is comfortable. Much better than the normal carbine length handguards that you see on 16″ uppers.

Reliability: * * * * *
I’ve fired hundreds of rounds through this upper and thousands of rounds through its brothers. Keep it clean and you’re cool.

Customization: * * * * *
There’s a full length top rail and points to mount side rails. You can hang as much crap off this thing as you want but as it is it’s a nice, slick, clean looking setup.

Overall Rating: * * * * *
This is a great lightweight upper. The only reason I wouldn’t use it every time I go to the range is that the ammunition is excessively expensive. Once prices come down (and my poor can makes a jailbreak) I don’t think I’ll ever leave home without it. The only thing I’d change is to allow the buyer the option to change out the muzzle device for one that doesn’t ping, but that’s just a personal preference.

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  1. At first I was like ‘Fuck this guy is nabbing photos from gunnit!’ then I rememberd who you were and yeah. Gun looks awesome!

  2. Two big misconceptions to note from just skimming this article.

    Barrel length doesn’t really impact accuracy, it impacts velocity. A projectile with a higher velocity will stay supersonic for a longer period of time, allowing longer distances shots. That is not the same thing as accuracy. A 16″ SR-25 shoots just as accurately as a 20″ or 24″ version. It’s just not as effective at extremely long ranges, ranges that really aren’t the domain of semi-automatic rifles anyway (just ask SOCOM). I think this myth come from snub-nosed revolvers and sub-compact pistols where the dramatically shorter sight radius, along with the increased felt recoil and muzzle blast, reduce accuracy. People just assume it’s the shorter barrel when it really isn’t.

    Cleanliness really isn’t what keeps a DGI AR reliable. The areas critical to weapons functioning are kept clean by metal on metal contact. Which brings up the thing that really does keep an AR reliable; lubrication. You can shoot a DGI AR for thousands of rounds without cleaning it and not have any issues. Proper lubrication and timely replacement of wear items (action spring, gas rings, extractor and extractor springs) are the critical things to think of when trying to keep an AR running.

    I think this myth comes from the military and experiences in Vietnam. The 5.56mm ammunition sent over with the first batches of the M16 rifle were not well suited for the rifle at all. On top of causing the weapon to cycle at over 1000 rounds per minute (far to fast for the magazines of the day to feed), the powder was highly corrosive and sensitive to moisture. Cases would swell and/or corrode in the bore and become stuck.

    With modern ammunition, it’s really not necessary to clean the AR all that often. Some people do more damage than good when using harmful cleaning products and procedures. Lube it and it will work.

    As for the .300 BLK, I think LWRCi is going to do a version of their UCIW (super short AR for a British contract) chambered in it. I’ll probably have to end up paying a tax stamp and getting one, along with some dies for my XL650.

  3. I agree with Nathan
    I bought my acc 300 black out in February 2016 took it to the range 3 different brands of ammo, 3 different grains.208,220,180, only the 220 semi worked. Called the company they said send it back. After a 2 month wait got it back went to the range now the 220 does not work.
    I called asked what was repaired they said they did not know the first call. I was told to return the weapon which means sit around till the ups guy comes with the label. That’s right sit all day till the come. You are not allowed to print their label and ship your self.
    I sent the rifle back in July still no weapon. I called 5 times (once a week) so far and told every time they will check and call me back. NO CALLS BACK.
    During 1 of the calls I was told it could take a year to repair.If you want your money back they get 3 tries to repair it.
    Which could be a 3 year wait just to even get to that point. Then who knows how long and how much do they give you back with a 3 year old gun.
    I even wrote the main company (Remington) 2 weeks ago. I never even got a letter or a single word from them.
    I know there can be problems in any thing that is made. How you handle the problem is a major issue.
    Remington has FAILED in every way

  4. Robert and a Nathan: this is why we have attorneys. A letter from one is not that expensive. It may do nothing, but it’s better than just sitting and waiting.
    I have a .300 Blk AAC upper. Fortunately for me, it has been without issues.
    I am not happy to hear about the terrible customer service,
    I just hope I never need it!

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