Short barrel AR noise levels

[Mark D]

Just curious, what's the appeal of the super short 5.56 rifles, like 7.5" inches? I was under the impression that 5.56 mm became pretty anemic in barrels shorter than about 10.5".

[Paul Blackburn]

Does the 5" to 9" 300 Black Out not have similar blast/concussion?

[Screwball]

Just curious, what's the appeal of the super short 5.56 rifles, like 7.5" inches? I was under the impression that 5.56 mm became pretty anemic in barrels shorter than about 10.5".

Probably people think they look cool…

My limit is 11.5” in a 5.56mm. To be fair, I think the only sub-10.3” barrel 5.56mm I’ve ever seen really marketed towards L/E was that DPMS Kitty Kat. Stag put out a few and I have seen uppers offered on PSA. But end of the day, it’s more for fun. I have two ARs and a MP5 clone that have binary triggers… completely for fun.

.300 Blackout did change that, as it was optimized for those shorter barrels. I do have a 6” AR, but it is 9mm, takes Glock magazines and is roughly the same OAL as a 16” AR with the Dead Air Odessa.

For my SBRs (minus the 9mms), I usually have something to direct the blast forward. Before suppressors, I had one of the KVPs. It wasn’t bad for the price. I also had a PSA AK-P with their Krink device. Behind the gun, you are good. Off to the side, you feel your guts rattling around.

I switched to the Griffin Taper devices so I could easily swap my Griffin Bushwhacker 46 among ARs… but had to pull it off my truck gun; Taper wouldn’t let the gas piston come out. Put an A2 on and got the A2 adapter from Griffin. It works and gives me flexibility to the couple ARs that I kept the A2 on. I do have their blast forward device, which works well… but when it’s between that and suppressor, I’m picking the suppressor. But the round going supersonic has a lot to do with the added noise. I always double up when shooting rifle rounds. Usually shoot both at the range, so I tend to have both in. But don’t notice a difference between SBRs and 16”+ rifles.

I keep my Bushwhacker on my truck gun majority of the time. Shooting without ears will still cause damage, but less than if it was unsuppressed. I keep a pair of foam plugs tucked on the gun, in case I got the opportunity to toss them in…. but the likelihood is low. In the end, I make sure I use ear protection during training. Hopefully if I had to use the gun(s) in real life, it wouldn’t cause too much damage.

[mmc45414]

Every couple of years someone floats the idea of getting mufflers (technically AND legally correct description )

I have mentioned to people the irony of it being illegal to put a muffler on my gun while being illegal to take the muffler off of my motorcycle, and the people most upset about a loud bike would be the first to wring their hands about "silencers".

Years ago I was shooting next to my friend, he with a 26" Rem700, me with one of my typical 16" ARs, and I was stunned by the realization that ten inches made that much difference (I will say it first: That's What She Said...). I do have a 7.5" upper, but when I bought it I knew it was just a (cheap) silly range toy. TBH, I do not own a can, and I really do not really love the 5.56 cartridge anyway, but is just part of the landscape at this point.

Some of all of this initiated my interest in 300BO, and looking at the powder burn rate chart illustrates this. This is a chart of relative rates, and that may mean there are lots of products between that range, but 300BO is basically working with the slow end of pistol powder:

[O4L]

So I have an 8" 300BK that I haven't fired yet. Am I going to hate shooting it with an A2 style muzzle device?

I have subsonic 150 grain and supersonic 200 grain ammo at this time. I plan on trying 110 grain v-max ammo for hunting.

[GJM]

Purely in the interest of science, I think TGS should arrange to be 25 yards down range of someone with a 7.5 5.56 doing mag dumps on steel in the adjoining bay, and let us know what that sounds like!

[GJM]

So I have an 8" 300BK that I haven't fired yet. Am I going to hate shooting it with an A2 style muzzle device?

I have subsonic 150 grain and supersonic 200 grain ammo at this time. I plan on trying 110 grain v-max ammo for hunting.

I was initially concerned about my Rattler, with a 5.5 inch barrel. With 110 Barnes, it is not anywhere near what I expected. To my ears, an 8 inch .300 BLK is similar or slightly quieter than a 16 inch 5.56.

[O4L]

I was initially concerned about my Rattler, with a 5.5 inch barrel. With 110 Barnes, it is not anywhere near what I expected. To my ears, an 8 inch .300 BLK is similar or slightly quieter than a 16 inch 5.56.

Thanks. That is kind of what I was thinking but I haven't really looked into it.

I bought it on a whim because I got a good deal. This is my first 300 BK and my first short barreled AR.

[Kyle Reese]

Just curious, what's the appeal of the super short 5.56 rifles, like 7.5" inches? I was under the impression that 5.56 mm became pretty anemic in barrels shorter than about 10.5".

Some people want to look cool on the range, I suppose. On my personal carbines, I don't go with anything in 5.56 sub 11.5", and those are all shot suppressed.

[HeavyDuty]

Just curious, what's the appeal of the super short 5.56 rifles, like 7.5" inches? I was under the impression that 5.56 mm became pretty anemic in barrels shorter than about 10.5".

Because they’re fun? Some rifles can just be recreational.

My personal crossover point between a serious and non-serious 5.56 is 11.5”, but I do have a new 10.5” upper I’ll be trying out.

A couple of years ago I was offered a deal on a new 5.56 Rattler that was barely more than a lightly used MCX lower end would have cost me. I bought it, of course and it allows me to have a second lower for my set of MCX uppers.

A 5.5” 5.56 is totally impractical and shooting it makes me giggle. I just ordered a .22LR conversion bolt for it so it will have a more practical use, too.