M*CARBO Brotherhood

Short Barrel AR Effectiveness

For any of you who are curious.



Thanks boss…Great video.


Thank you for providing a scientific test, I have seen many extrapolations of theoretical data that sounds so polite and polished. Nice but not always accurate. I believe what really matters is when the metal hits the meat. Those water jugs do a wonderful job of approximating a thin skinned animal with even a lower viscous internals than the living. A great test of the worst case senario. If I were bound to a 5.56 for close contact work, I would feel well armed for the engagement. Well done Sir!


@hrfunk Never stop taping and posting Howard. Very informative. :+1:


Makes me wonder how effective those micro 4.75" barrels are.
I have one but have done no testing. Only shot it a few times.
Seems like bullets start tumbling as soon as they leave the barrel.

Great video and information, as always. Thanks for posting.
I gave it a thumbs up on YouTube, same as all your videos.


Had to explain this concept to my kids a few times. They understand bits/bytes 1s & 0s, but still cant grasp the concept of video on a tape.


Great video. Fun, informative day at the range.
There are some other physics to consider with the test, one being hydraulics. Like to see same test ranges with ballistic gel to differentiate between hydraulics and fragmentation.

@ValorSolo don’t have a 4-1/2, but here’s my 7-1/2" pistol tracked with my labradar out to 70 or 80 yards. Using @hrfunk 's effective velocity of 2350+/- definitely a 50 yard tool.

40 gr pills

55 gr commercial 223

55gr 5.56

62 gr green tips


I have not finished the video. What I have seen has been shown elsewhere. First thing is that even a slower 55 gr .224 caliber bullets that does less damage is going to hurt and if shot placement is correct will be lethal. For the short barrel expanding 5’56 bullets are the correct choice. There is still sufficient muzzle energy to destroy tissue if the bullets will expand.
But I even go further and use 300 blackout and 7.62x39 in short barrel. I have some copper barnes bullets and those should work well when handloaded for short barrel guns.
All of this may be moot when the final rule on braces comes out and I have to either pin and weld flash hiders to get 16 inches or destroy the brace to comply with the ATF. I certainly hope they chose not to implement that rule.


Sgt. Carter! Pyyyyllleeeee!!

My 8” 300BLK build has shown to be devastating out past 150yrds. 150gr MK (full speed)and 194gr Lehigh (slightly supersonic). I am waiting on some Speer 150gr 300BLK specific bullets to become available. I think it may be the best option at a reasonable price point. Short barrel weapons are found to be as accurate as the user in my testing. Make it fit the user, just like track shoes.