How do AR15 rifles (not carbines) suppress?

[Dan Forrester]

I have a factory LMT fixed butt stock rifle lower with a 100% Colt M16A2 upper and would like to put my KAC NT4 suppressor on it. I have never read of anyone discussing how full length 20 guns with rifle buffer systems work suppressed.

Does anyone have any experience with a setup like this?

Thanks, Dan

 

[Ranb]

I had a 20" Colt Comp H-bar that suppressed well enough. It was hearing safe with my homemade can as long as I'm not shooting under weather protection. Without the silencer attached it ejects to the rear, with the silencer attached it ejects forward. The brass flies out about the same distance either way. As a lefty I notice more gas and crap flying into my face when shooting suppressed. It now has a 20" MN DMPS upper and operates the same. I plan on getting an adjustable gas port for it soon.

Ranb

 

[YZ]

Poorly. Not as quiet as a bolt action rifle. The exception would be a piston-operated AR with an adjustable gas pressure valve, such as the SIG 556. Closing it will make this AR manually cycled, but quiet as they get.

In DI rifles, or with an open gas valve, some noise will escape through the back door. There will also be burned gas blowback in your face. Chamber fouling will be much worse than usual. depending on the number of shots fired. Bottom line, it is interesting at first, but the side effects will be bugging you soon.

 

[LawBot5000]

Bolt noise is always accentuated to the user because the bolt is close to your ear. From 50 yards away, the bolt noise is invisible and the muzzle noise dominates.

The bolt noise also sounds loud compared to the noise coming out the gas port.... which on a sig is just as substantial as the muzzle report. Sigs and AKs generally make poor hosts for this reason.

The AR-15 with DI gas system is great for suppression because the gas system is pretty much sealed up tight.

I own a very quiet integrally suppressed AR-15 in 45 acp and a 22 can. I've shot nearly everything on the market at one time or another.

 

[dprice3844444]

they make a forward assist assebly that is vented for use in suppressed ar-15's to handle the increased back pressure
ar-15 silencer vent
http://www.silencertalk.com/forum/viewtopic.php?f=56&t=56780

 

[ny32182]

DI AR will suppress considerably better than a piston operated semi because the gas system is better sealed.

I wouldn't expect a lot of difference between a carbine and a rifle. There is no fundamental difference between them... in both cases you will have muzzle blast tamped down, supersonic .223 bullet, and extremely similar gas systems.

 

[YZ]

Pay attention. The difference shows when the gas valve is closed in a piston driven AR. That's basically what the closed pisition is for.

 

[ny32182]

Closing off the gas system kind of defeats the point of having a semi auto, doesn't it?

 

[YZ]

Not really. It only gives your semiauto the new capability when maximum suppression is called for. The suppressor will still work with a partially closed gas valve, just not to its full potential.

 

[YZ]

Lawbot
Just now spotted my typo. I meant SIG 516. The AR SIG. Reciprocating bolt handle is indeed noisy, you are correct in that regard. I also tried a Mini14 suppressed. No good.

 

[Dan Forrester]

I guess I’ll just hold off then. I was somehow hoping that with the longer gas tube and buffer system it might function a little smoother.

Hopefully one of these days Noveske can get some swithblock barrels (or any barrels for that matter) in stock again.

Thanks for the information,

Dan

 

[LawBot5000]

You're still debating something that is irrelevant. Pull the bolt back and release it. It makes maybe 80-90 db of noise. Even the quietest 22 LR can is 110-120. Most 223 caliber Ar-15 cans are going to be in the 140db range including bullet noise, low 130ish from the muzzle.

There is no way in hell that stopping the bolt from moving makes the slightest difference, except to the ear of the shooter.

 

[YZ]

While shooting suppressed for sports, listening to the rifle going click clack is kind of fun.

 

[Markm87]

Suppresses Good! Not Bolt gun good, but pretty good.

It's unwieldy as hell, but I used to keep a mount on one of my 20" ARs and it was fun to shoot off a pack.

 

[YZ]

Good point, the AR gets nose heavy with a can on. That's another detraction to me and those who don't shoot much from a bench rest. Especially with a 20" barrel.

 

[Dan Forrester]

Actual suppression with any ar15 rifle is less of a concern to me. I know the thing is never going to be quiet unless I go 300 blackout or something. If I want really quiet I’ll go with my .357 rifle with 9mm suppressor.

My main concern with suppressed AR’s is increased wear on the rifle, gas in the face, increased fowling and things like that. I really hate swapping out springs and buffers just to get it to run reliably suppressed only to have it not function with the suppressor off.

Dan

 

[Markm87]

Cans are messy. Get froglube to keep it running and wet. 300 blk is useless nonsense.

If your gun isn't overgassed to start with, you won't need to swap any parts. I've run my can on 20", 14.5", and 11.5". My POS Sabre 11.5 was monumentally over-gassed with some .080" ridiculous barrel port.

I had to put an insertable gas port to choke it down to .065" or something.

 

[taliv]

i have a 10" noveske switchblock with 4" mini brevis suppressor. it works great.


i did try froglube for a while but went back to slip2k

 

[Markm87]

Did you no like Froglube? It looks messy, but it keeps the bolt wet.

 

[W.E.G.]

Any .223 is going to be loud enough, even with a suppressor, that you will need to still wear ear protection. Barrel-length will make little difference.

A suppressed .223 sounds about like an un-suppressed .22 magnum.
If you shoot it in a confined area, one shot will make your ears ring.

If you want to run "sub-sonic" .22 loads, consider getting some Mexican "Colibri" ammo and a cheap .22 bolt gun.

...and yes, suppressed AR's make a dandy mess of your trigger group after only a few shots. Most of the mess comes right back down the barrel. So, the fancy-schmantzy "piston gun" won't help with the mess.

Unless you shoot on a windy day, you'll get a big un-breathable smoke cloud around your face too.



If you take it on-and-off the rifle regularly, its just a matter of time before it goes back on slightly caddywampus, and you get this.
Same thing too if you let others shoot "their ammo" in your rifle,



...which costs this much to fix.

 

[taliv]

Did you no like Froglube? It looks messy, but it keeps the bolt wet.

i did. smelled great at least.

but my reloads / suppressor combo were just super dirty and it seemed to get sluggish faster than slip2k. not scientific test or anything. and i only ran maybe a couple thou rounds.

 

[YZ]

I flush mine with Gun Scrubber.

 

[mtrmn]

Actual suppression with any ar15 rifle is less of a concern to me. I know the thing is never going to be quiet unless I go 300 blackout or something. If I want really quiet I’ll go with my .357 rifle with 9mm suppressor.

My main concern with suppressed AR’s is increased wear on the rifle, gas in the face, increased fowling and things like that. I really hate swapping out springs and buffers just to get it to run reliably suppressed only to have it not function with the suppressor off.

Dan

I run my YHM 762 on my Colt 20" with no added problems at all. Seems to work fine with/without the suppressor but I don't put multiple thousands of rounds through it, so I don't know about added wear.

 

[YZ]

I agree, shooting a canned AR probably wears out you sooner than the rifle.

 

[FullEffect1911]

I run a YHM .30 cal Phantom on a 16" AR with a carbine gas system. The "puff" of blowback gas is annoying out of the charging handle but was mostly fixed with a gas buster charging handle.

I also switched to a H3 buffer which works fine both suppressed and unsuppressed. Ejection is slightly different but that doesn't bother me.

I think bringing the sound signature down from mid 150's db to around 140 makes a big difference.

Same can on my Ruger scout doesn't really seem all that much quieter really.