Ask Foghorn: Zero Distance for 300 AAC Blackout?

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Seth writes:

What are you using for zero distance for your blackout? I am big fan of the 50/200 zero in .223/5.56 and I am hoping there is something similar for the blackout round. I did a little experimenting on trajectory software, but didn’t come up with anything concrete.

The good news is that the old 50 yard zero works pretty well for 300 BLK as well. Here’s why . . .

300 AAC Blackout is a fantastic hunting round. So long as your target isn’t much over 100 yards, that is. While having a chunky projectile is a nice improvement over the standard 5.56 cartridge, it does mean that you lose some muzzle velocity. And in turn, the trajectory past 100 yards for this gun has been described as “rainbow-like.”

However, over that 100 yards the trajectory is remarkably consistent. With a scope height of 1.5 inches, the parabolic arc of the round peaks at 50 yards and returns once more to -1.5 inches at 100 yards. Or, in terms of hunting, a variation of less than the profile of a deer heart over 100 yards.

In my opinion, the 300 BLK round is the perfect gun for game under 100 yards away. Or, in other words, just about anything in South Texas (where I live). But when you start moving past 100 yards, its time to break out the zippier calibers. At 150, the round has dropped 6 and a half inches. At 200 its almost a foot and a half down.

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I’m not saying that it can’t be done. I’m regularly singing steel at 250 with my 300 BLK rifle, with a nice +3.4 Mil hold. But that’s not a shot I would be comfortable making on wildlife. Not humane.

And that’s why I like the 50 yard zero. It keeps the trajectory nice and flat for the distance that I’m comfortable killing things, but once you reach the end of that 100 yards its like the thing falls off a damned cliff. You could get a little more distance out of a 25 yard zero (under 1.5 inch drop at 150 yards), but then the bullet moves through a little over 3 inches of variation over 100 yards compared to 1.5 inches with the 50 yard zero.

[Email your firearms-related questions to “Ask Foghorn” via guntruth@me.com. Click here to browse previous posts]

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About Nick Leghorn

Nick Leghorn is a gun nerd living and working in San Antonio, Texas. In his free time, he's a competition shooter (USPSA, 3-gun and NRA High Power), EMT-B and enjoys mixing statistics and science with firearms. Now on sale: Getting Started with Firearms by yours truly!
This entry was posted in Ammo, Ask Foghorn, Guns for Beginners, Hunting, Rifles. Bookmark the permalink.

28 Responses to Ask Foghorn: Zero Distance for 300 AAC Blackout?

  1. avatar jmk says:

    are you talking subsonic or supersonic loads?

  2. avatar William says:

    Most of my Blackout problems have involved Mezcal.

  3. avatar Accur81 says:

    At this point I think finding ammo for a 300 is more difficult than zeroing one.

    • avatar Tod says:

      Agreed, I just got mine before the craziness so it sits having only been fired once. The only stuff I can find is $1/round and I don’t need it that badly!

    • avatar OhioShooter says:

      Can we possibly make it through one gun review without someone whining about ammo? I really need to stop reading the comments section…

    • avatar Dan says:

      Reload. Even when 300blk ammo was available it was expensive.

      I love my $0.26/rd 220gr subsonic 300blk loads.

      *hugs his progressive reloading press*

  4. avatar Nobody says:

    Good article. Thanks!
    For the future, can you shoot like a little girl?
    http://www.breachbangclear.com/site/10-blog/301-fight-like-a-girl-watch-this-little-girl-shoot-like-a-boss.html
    I thought this was great.

  5. avatar Josh says:

    I still don’t really understand the fascination with 300BO. With those numbers, it competes with the 45-70. It seems like a 1-trick pony — subsonic or nothing at all.

    • avatar Swarf says:

      Or even the 30-30. I’m not really seeing the appeal. And I’m not being snotty about that, I really want to know.

      Is it really better than 7.62×39 or 30-30?

      Nick has probably done a comprehensive article on this very subject and I just missed it.

      • avatar Will says:

        No I definitely don’t think it’s ballisticlly better than ol 7.62×39. I think it’s only benefit is that it functions better in an AR platform than 7.62×39, has more “bullet” than 5.56, while still using the same hardware except the barrell.

        • avatar Nathanredbeard says:

          I don’t own one, but that’s my take on it. It provides a load comparable to a .30-30 or 7.62×39 that functions perfectly in an AR-15. I personally prefer .270 cal and so I lean towards the 6.8 SPC because of the better long range performance, but .300 Blackout does what it’s supposed to do really well.

  6. avatar Josh says:

    I still don’t really understand the fascination with 300BO. With those numbers, it competes with the 45-70, but only external ballistics. The terminal ballistics have got to suck. It seems like a 1-trick pony — subsonic or nothing at all.

    • avatar stormchaser says:

      Well, the 300blk is great for subsonic, with very little lost going from a 16″ to a 10″ barrel. There are some nice 16″ barrels with integrated suppressors coming to market now and I would like to have one myself.

      Additionally it is superior to 5.56 for hunting with supersonic (to limited distances) and fits in the mags you already have.

      So you could buy the upper and use it subsonic as a defensive rifle or as a CQB rifle and change to supersonic for additional uses. If the military or law enforcement would pick it up then the ammo price would theoretically come down as well.

    • avatar wombat338 says:

      I can’t wait to get a .300BLK barrel for my XCR. My fascination with the cartridge is that it should make for a superlative defensive and (once the cost comes down) plinking round. It uses both unmodified AR-15 pattern mags and a standard 5.56/.223 bolt, meaning that I’ll be able to change calibers in about 2 minutes, by just swapping barrels. While 5.56×45 is not, in my opinion, a good defensive (or military) round, inside 100 yds (the maximum practical range I’d use a defensive carbine on my property), .300BLK leaves a big enough hole and packs enough punch to get the job done. Finally, although I’d use supersonic bullets (still with a suppressor) for defensive purposes, shooting subsonic suppressed would be a hoot.

  7. avatar Jimbo says:

    This article is just about the most horrible zeroing advice imaginable. Assuming you’d like to be able to always hit within a 4 inch target, if you were to zero the 115 grain UMC loading @2200 FPS at 23 yards (25 is close enough) you get a range of 181 yards wherein the bullet neither rises or falls more than two inches below the point of aim. Leghorn needs to stop being paraded about as an expert on well, just about anything firearms related…

  8. avatar M.ia says:

    Barnes 110gr TAC-TX is awesome in 300 blackout. Accuracy has been 1 MOA or less with it. I tried catching a bullet in a tub of water that was 24″ long set at 50 yards. It passed completely through with plenty of energy left over. This happened twice and i didn’t find the bullet as i neglected to bring my boxes of newspaper for the backstop. These were reloads made with 19.3gr of h110 with OAL of 2.25. Not sure on fps. (i have no chrono) no signs of over pressure though. And I’d have no problem using these on deer or hogs of any size. My upper is from SOTA Arms. No malfunctions of any type from it in the first 400 rounds. Both reloads and 115gr UMC ammo.

    My zero is set at 50 yards as well

    I love my 300 blackout. I would rather shoot it than any other rifle i own. It is much easier on the ears than .223 and shoots 110gr v-max bullets to 1 MOA. Which is now my home defense round.

  9. avatar JAS says:

    6.8 SPC. “what’s the best all around variant?” , my answer is the 6.8 SPC.”
    -Bill Wilson

    And that’s all I have to say about that.

    Forrest Gump

    • avatar Accur81 says:

      Not sure if anyone is still reading this thread, but Silver State Armory has 6.8 Nosler Accubond 110 grain in stock. I just ordered 10 boxes of Pro Hunter as well.

      Not bashing the 300 AAC, which I think is a cool caliber, I just don’t know if I’ll be able to feed it given the massive political stupidity regarding the 2A.

  10. avatar Seth says:

    Well, since I had my question posted, guess it was time for me register finally.

    Anywho, since I sent out this email some time back, I have had a chance to look into it further, and had similar results to Jimbo. If I set a zero at 200 yards, it puts me at around 1.5″ high at 100, and back to zero at 35 yards or so. Close range works perfect for pigs, hold low for 100 on white tail, and back dead on at 200.

    All that said, Nick may very well have a point concerning a kill at 100 plus yards. I would have to be very confident in an accurate hit at long range, and take into account the animal size as well.

  11. avatar 2Savage says:

    Guys, the 300 Blk is a good deer/hog round out to 200 yds or so. The trajectory is a little rainbow like and the 7.62×39 and 30-30 are pretty good comparisons. Let’s see, the 7.62×39 has been an awfully effective man-killer for over 60 years and the 30-30…killed more deer than any cartridge ever. So, the 300 Blk only matches those two huh? What’s the problem? It is an incredibly efficient cartridge and with the Barnes Tac-Tx an awesome killer. Better than the 5.56-hell yes. Gravity is a constant companion. Hits at longer distances are not an issue with a range finder a drop chart and a good rest. And, it all fits in your AR-15 envelop with only a barrel change. Sweet.

  12. avatar Daniel says:

    I was JUST wondering this today. Wonderful to know!

  13. avatar thedonn007 says:

    So, since I already have a 5.56×45 AR and .300 blk AR. What caliber should I use for hunting over 100 yards in the AR platform?

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