300 AAC Blackout Subsonic Velocity Data

As mentioned previously, I am working with a series of 300 AAC Blackout uppers courtesy of Deliberate Dynamics and Rainier Arms. These uppers have Noveske stainless steel barrels and will be run through a series of tests to determine their suitability for various purposes, both “military” and “civilian.” Jim of Deliberate Dynamics did the shooting today, while I “shot” photos. I particularly like this shot, which shows what I believe to be a bit of flame coming out the ejection port along with the case.

8" Noveske 300 AAC Blackout

One of the first things we wanted to do was see what the performance of the 220 grain subsonic load was from these uppers. Since we had 8″, 10.5″, 12.5″ and 14.5″ barrels at our disposal, a good chronograph, and factory ammunition, it was a fairly easy task. These are preliminary numbers, and will be followed up with more thorough data analysis – but for now, they’re pretty solid.

14.5" Noveske 300 AAC Blackout Chronograph Data

I’ve been loading 300BLK for a few months now, but I think most people will be interested in the performance of factory ammunition. In this case, it was Remington R300AAC8 – the aforementioned 220 grain subsonic stuff. Although supersonic loads – and factory brass – have been promised for a very long time now, it’s disappointing to see that they have not been forthcoming.

Noveske 300 AAC Blackout

We encountered no functional issues, which was a good sign for both the caliber and myself, since I put the uppers together. The Troy mags, as well as PMags, fed the fat 220gr loads just fine. If you’re not familiar with 300 Blackout, it uses 5.56 bolts and magazines, and a modified 5.56 case that’s shortened 10mm and necked up to .30 caliber. The advantages of 5.56 mags and the strength of a 5.56 bolt, as well as .308 diameter projectiles, make this a much better choice than 7.62×39 for the AR-15 platform.

8" Noveske 300 AAC Blackout


As for the performance of the subsonic load, all shots remained subsonic, which is, of course, a good thing. However, this means that the guys with 8″ uppers are going to be using a load that’s a little slower than it could be, just so the guys with 14.5″ and 16″ uppers don’t have that supersonic “crack.”

12.5" Noveske 300 AAC Blackout

The 8″ averaged 954fps, the 10.5″ 993fps, the 12.5″ 1014fps, and the 14.5″ 1025. This is clearly a load that’s optimised for shorter barrels. However, I wasn’t impressed with the standard deviation – over 40 in all but one example. And the extreme spread was, well, extreme, exceeding 100fps in several cases.

14.5" Noveske 300 AAC Blackout

I would like to see more ammunition available in this caliber. Not only would more loads be nice, but I’ve never found Remington ammunition to be “the best,” or even above average. Right now, though, this 220gr load is just about the only thing I can find, other than expensive Cor-Bon stuff, and 175gr CMMG ammunition that reportedly won’t cycle in anything but CMMG uppers. I’ll be loading various projectiles, but as I said above, hard data will be presented with factory ammunition. My final report will be a comprehensive evaluation of the caliber.

22 thoughts on “300 AAC Blackout Subsonic Velocity Data”

  1. What I’d like to hear about is subsonic load’s effects on target. How will the 220 grain bullet hit harder and do more damage than my 230 grain .45ACP that runs about 900 fps?

    The only place I would want to use this caliber in inside my home. I’m unlikly to need to hide in a bush and whack someone silently, so my main issue is muzzle blast deafening me inside my home. AAC posted a video showing them shoot a pumpkin with a subsonic and it punched a hole through it. Then they shot it with a supersonic expanding bullet and it exploded.

    Now, at some point my state might decide to allow silencers for hunting, and I can re-evaluate ammo for hogs, but for short range, against home invaders, silenced, what advantage does subsonic ammo give?

    1. In your example, I would probably choose supersonic, fragmenting ammunition with a can. The can would take the edge off, but the supersonic/fragmenting ammunition would offer improved terminal ballistics.

  2. The main advantage is that you don’t need 2 guns and 2 calibers to shoot subsonic and supersonic, you can use the same rifle and just shoot a different load where you need increased range, terminal ballistics, etc. At the same velocity I would think .45 ACP would have better effects on soft tissue as basically the only damage you get from a round moving that speed is the hole that it makes, .45 is bigger. That being said, that doesn’t take into account which types of projectiles are offered in each caliber. I would think at this time, .45 ammo has been developed a lot further into order to offer better expansion at the lower velocities. The subsonic 300 BLK I have seen appears to be a normal BTHP rifle round. Other than a better BC, I don’t see how it can out perform .45 ACP on soft tissue. Barriers, glass, over-penatration, etc…… who knows. I know .45 doesn’t go through much in the way of barriers, so I would think 300 BLK would be better there, but that is just a guess.

    1. I have some gelatin, it won’t be comparable to other people’s testing because I am not a professional jello mixer, but it should provide a general comparison between the 5.56 and 300BLK loads that I test.

  3. Thanks! I’m looking forward to supersonic impressions, and maybe a recoil comparison video to a similar rifle in 5.56? My big questions about the round revolve around non-suppressed use, and is it worth the time vs. a similar build in 5.56, since I’m headed to a non-suppressor friendly state in the near future.

    As always, I appreciate you taking your time to check this stuff out!

    1. That’s a good idea. I did notice a bit of a difference between 5.56 and 300BLK, but then again, I also noticed a difference between my supersonic 300BLK loads and the subsonic stuff. I’ll try to compare 5.56, 7.62×51, 300BLK and maybe 6.8 in the final video.

      1. Oh, if you could get a 6.8 in there, that’d be awesome! That’s probably it’s biggest competition, supersonically (not a word, but you know what I mean 😉 ). I know the 6.8 has longer legs because of the increased case capacity, but a good recoil comparison would be great!

    2. i have both 5.56&300 blk out i could not feel any difference in recoil. 5.56 has more muzzle blast. the 300 is more accurate my 3rd & 4th 10 shot groups out of the box one hole @ 100yrds.

  4. I notice that in two photos there is a muzzle brake on the barrel – one appears to be a BABC and another looks like an AAC brake. Another photo has an AAC Blackout flash hider. Did you notice much difference in felt recoil or muzzle rise when using the two brakes vs. flash hider?

    1. Difficult to say, since I wasn’t doing the shooting. We’ll see if Jim chimes in. He’s a busy man. I plan on getting back to the range with all of the uppers in their current configurations this week.

  5. Great write up. I had a chance to shoot a 16″ 300BLK full-auto suppressed and it was badass. The round seems super slow at distance (200 yards), but inside a shoot house, it was perfect. Full-auto was very controllable and the suppressor was ‘movie quiet’ outside, I would say comparable to a suppressed .22LR. Inside the shoot house it was more like an unsuppressed .22LR. Still plenty quiet. We were shooting factory 220 grain 300BLK subsonic ammo.

  6. I have a few 6.8’s that I can bring out next time or maybe we can meet in oregon and do some more this winter. I have a 12″ and that 8″ psd in 6.8, and plenty of ammo (85 gr tsx, and the 110 TAP).

    I think 6.8 is going to be better supersonic, especially in bbl lengths over 10″, it should crush 300 BLK out of a 12″ bbl say, but we’ll have to wait and see. I am just looking forward to seeing apples to apples comparisons instead of most of the data that is out there right now. Also I will have the form 4 back on the AAC SDN-6, so we can get some suppressed shooting in. Looking forward to it.

  7. On the recoil, it was pretty light in all configurations, but I wasn’t really focusing on it all that much for what we were doing. I think it will come into play more with the supersonic stuff.

  8. Not to detract from 300blk but you said you were going to load your own. And in previous videos you have said that you also have shot your own reloads. Would a video on reloading equipment stray too far away from your concept of vuurwapenblog? Thanks!

  9. We have been working with the 300 Blackout and have had no problems with the CMMG ammo. We have been working with 7.5″ through 16″. Of course they are not Noveske barrels. As for the factory ammo avaiable, we have been using both Rem. and CMMG. Also some various hand loads with LIL Gun and are getting sub min, @ 100 yds, even with the shorter barrels.

    respectfully, Ron STS Arms,LLc

  10. Hello

    Anybody please let me know what exact barrel of the one on 1st pic is?
    Is that 8.2″?

    Thank you


  11. The 300 is a good option for CQB. With the can is super for home protection or in the car. In pistol config it is a pretty good PDW. I like it for protection details, with a can kept by #1 (commander) in front left seat. It is used with 230gr fragmenting @ 1150 for duty and 230 cast lead @1020 for training. We produce all our own munitions in house. (357SIG 125XTP @ 1350, 45ACP 230 XTP @ 900, 5.56 77OTM @ 2850, 5.56 64SP @ 3100, 5.56 55FMJBT @ 3400 for field use and many other match and training rounds. The 300AAC is new and we are working on the best sub sonic round. This has replaced our AR 9mm platforms. We still have to do barrier tests, I have watched lots of video, real world live is the real test. I have seen vid of it making a massive tumbling wound in ODjell. The 45ACP is an expander the 300AAC is a rifle round and will make a rifle wound with proper loading. Long skinny ogive and a long heavy meplat causes the tumble effect. If it frags and tumbles this is optimal for massive trauma and quick stop. The 5.56 frags as it tumbles in the 77OTM and 55FMJBT, The wound is massive at 200yards and in with 14.5 bbl. At CQB ranges 50 feet and closer the 300AAC has the potential to replace all other caliber of the sub gun. The lighter bullets do not intrest me as this is used for a sub gun for combat situations. If I was a hog or hunted deer with a roifle it would be the 125gr @ 2375 all day. I will have write-ups on my website in the future. I also use 1MOA or better rifles, which is easy with the 230gr loads. An adjustable gas block or tube is not needed if using the same basic loads which produce the same volume and pressures each shot. I tweek the gas ports and tube for optimal gas pressure. Most ARs are over gassed in stock configuration which leads to fowling and quicker wear. MORE TO COME @ ARGlock500, Google web page check it out!

    1. Thank you so much for your kind answer.
      One thing that I want to know is what barrel length used.
      It seems that the Troy TRX 7.6″ rail and Noveske 300ACC 8.0″ (not 8.2″) barrel were used on that pic 1st.
      In case, is it too tight to install can, the gap between can and rail?


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