Making an AR15 quieter, the weapon not the suppressor

[Dolomite_Supafly]

I have a Form 1 suppressor I have built. It has a 1.5" outer tube and a 125" inner tube with K baffles. The blast chamber of the 1.25" tube vents into the space between the two tubes. With ammunition at ~1,000 fps, and loaded specifically for a single shot, I can hear the hammer fall on my Encore rifle. I can also hear the difference in how different bullets fly so I know the can is capable of being really quiet. And even with the AR loads out of a single shot it is very quiet, not as quiet as the rounds using faster powders but it is still very quiet.

The AR itself is chambered in 300 Blackout with an 8.5" barrel. All I shoot is subsonic rounds. I also have a 9" Contender in 300 Blackout that is threaded for the suppressor. I have tried buffers from the super lightweight all the way up to a super heavy solid 4.9 ounce buffer and it does not seem to make a difference. The pistol length gas system has an adjustable gas block and is adjusted to lock back on an empty magazine, 1/4 turn tightening and it will not lock back so I am right on the edge of getting enough gas.

Shooting the same ammunition the AR is significantly louder, not just to the shooter either, than the Contender. I have tried every conceivable powder too. VVN105 seems like the quietest but WC 680 (a surplus equal to A1680) is pretty quiet as well. IMR 4227 is really quiet as well. The Lil'Gun loads and the H4198 loads are a little louder. I have tried 245 grains cast, and coated, bullets as well as 230 grain Lee cast, and again coated, bullets. I have recently tried some jacketed bullets and they seem a little quieter out of a single shot with single shot powders charges but when loaded to cycle the AR they are as loud as any other bullet. I was able to test, using a high quality microphone and software, the various loads against each other to determine which is the quietest but I have no clue on dB numbers.

Is there anything anybody can think of to make the gun quieter or is it just the nature of the beast. When I say loud it is about as loud as a Aguila colibri out of a pistol without a suppressor. Not painful by any stretch but still loud enough that it would be easily heard at 50 yards.

[batman4706]

I've had some really quiet loads with 5744, it leaves a lot of debris in the gun though. 4198 was the next best. I have the JP quiet recoil sprig too, which helps quiet the gun's noise some.

[McLarenross]

Ill second the JP captured recoil system. I installed it in my blackout and it really helped. The most noticeable sound with the can was the spring twanging inside the buffer tube till I put that in there. As with all JP stuff, its expensive but worth it.

[Dolomite_Supafly]

Ill second the JP captured recoil system. I installed it in my blackout and it really helped. The most noticeable sound with the can was the spring twanging inside the buffer tube till I put that in there. As with all JP stuff, its expensive but worth it.

If I go this route I will just make my own. I built one several years ago but gave it away.

[Doubeld]

I've had some really quiet loads with 5744, it leaves a lot of debris in the gun though. 4198 was the next best. I have the JP quiet recoil sprig too, which helps quiet the gun's noise some.

did your , or have you swapped out the spring and played with "fine tuning"

[sillycon]

What buffer weights have you tried?

I've gone from 3.2oz up to 5.6oz on my 9mm AR and I noticed a bit less chamber bark. I've been thinking about stepping up to a 8-12oz buffer, but I'm wondering if there is a big enough difference to warrant the cost (and extra weight!).

I realize DI vs blow back is a bit apples to apricots, but I'd think that additional buffer weight should still help quell the noise to some extent on a DI system.

[Dolomite_Supafly]

I have tried very heavy buffers as well as really light buffers. I also tuned the gas impulse with my adjustable gas block.

I was considering drilling vents opposite to the vents in the side of the bolt but after shooting my gun with the suppressor muzzle against the ground I realized the gun isn't loud at all.

[jdasilva]

Ill second the JP captured recoil system. I installed it in my blackout and it really helped. The most noticeable sound with the can was the spring twanging inside the buffer tube till I put that in there. As with all JP stuff, its expensive but worth it.

If I go this route I will just make my own. I built one several years ago but gave it away.

How did you make it?

[sillycon]

Did you see any marked difference with the heavier buffers? How heavy did you go?

I'd also be curious to see the home-made recoil system you folks speak of.

[LawBob]

I have tried very heavy buffers as well as really light buffers. I also tuned the gas impulse with my adjustable gas block.

I was considering drilling vents opposite to the vents in the side of the bolt but after shooting my gun with the suppressor muzzle against the ground I realized the gun isn't loud at all.

shake your buffer...it makes noise. get the spikes tactical buffer, no noise.

also the spring...I think JP makes a "quiet' spring to eliminate the boing boing...i hear good old dab of axle grease will do too.

[ThaDoubleJ]

Axle grease doesn't do anything, tried it. Tubb spring does a lot, but that spikes idea is a good one.

[BroncoAZ]

I am looking for ways to make the bolt on my 9mm AR quieter. I am using a Spikes ST-9X buffer (8.5 oz) with a +10% Wolff spring. The gun runs well with and without my Liberty Mystic, but the bolt going back into battery is very loud. I am sure the heavier buffer and spring contribute to the extra noise, but they are required to make the gun run and have the bolt hold open work correctly. Any ideas?

[hyrulejedi86]

I have the same problem with my 9mm AR, I can't shoot it suppressed without earplugs in the right ear because it's so loud.

[Dolomite_Supafly]

Ill second the JP captured recoil system. I installed it in my blackout and it really helped. The most noticeable sound with the can was the spring twanging inside the buffer tube till I put that in there. As with all JP stuff, its expensive but worth it.

If I go this route I will just make my own. I built one several years ago but gave it away.

How did you make it?

I have a lathe.

I have tried very heavy buffers as well as really light buffers. I also tuned the gas impulse with my adjustable gas block.

I was considering drilling vents opposite to the vents in the side of the bolt but after shooting my gun with the suppressor muzzle against the ground I realized the gun isn't loud at all.

shake your buffer...it makes noise. get the spikes tactical buffer, no noise.

also the spring...I think JP makes a "quiet' spring to eliminate the boing boing...i hear good old dab of axle grease will do too.

I run atomized copper in my buffers, they are dead silent.

I have since figured out a decent load as well as got my gas system tuned correctly. It is very quiet now.

[BCJ]

I made my own extra heavy buffer to quiet down my 9mm. I just used some 304 stainless and gutted an H3 buffer for he tungsten weights

H3 on top, mine in middle, 9mm bottom

[sillycon]

Have you found that for blow-back operated AR's the heavy buffer makes a difference in reducing chamber bark?

[Deathray]

A heavier buffer is definitely a requirement in a blowback AR since the inertia of the bolt and buffer is all that slows down the bolt during firing. (well, and the hammer to a lesser degree)

On a gas operated one, I run an empty buffer and an adjustable gas block. Less felt recoil and less noise. Heavy buffers on gas guns are a BS band-aid fix.

[sillycon]

As weight goes then, how much is too much?

I guess I'm going to have to make a buffer out of Ledloy or such and see what comes of it.

[sillycon]

So I made up a 10oz buffer over the weekend. I've got a design for a 13-14oz buffer as well, and have some ideas for even heavier ones if necessary.

I'll give the 10oz one a try this coming weekend and see if it makes any (subjective) impact to the chamber bark.

[andrewm]

So I made up a 10oz buffer over the weekend. I've got a design for a 13-14oz buffer as well, and have some ideas for even heavier ones if necessary.

I'll give the 10oz one a try this coming weekend and see if it makes any (subjective) impact to the chamber bark.

Any luck?

[sillycon]

So I made up a 10oz buffer over the weekend. I've got a design for a 13-14oz buffer as well, and have some ideas for even heavier ones if necessary.

I'll give the 10oz one a try this coming weekend and see if it makes any (subjective) impact to the chamber bark.

Any luck?

Subjectively, yes, the heavier buffer did make a difference. Shooting the gun suppressed sans hearing protection no longer left my ears ringing with this heavier buffer, and a couple of my shooting buddies also noted that the gun seemed quieter than usual (using my usual S&B 140gr subsonic ammo).

I have to get my hands on another set of tungsten weights so that I can "before/after" contrast an H3 buffer with my custom one using a sound meter.

I realize that my Radio Shack meter is not a "proper"/scientific test, but believe it is at least a bit better than "well, my ears didn't ring afterwards...".

Though, I'm also not guaranteeing DB numbers based on it either.

I also did up another one (this time in 304SS - what a bitch!) so I could give it to a buddy with an RDIAS and see what sort of rate reduction it would give. I should have a chance to test that in a couple weeks.

[Dolomite_Supafly]

So I made up a 10oz buffer over the weekend. I've got a design for a 13-14oz buffer as well, and have some ideas for even heavier ones if necessary.

I'll give the 10oz one a try this coming weekend and see if it makes any (subjective) impact to the chamber bark.

Any luck?

Subjectively, yes, the heavier buffer did make a difference. Shooting the gun suppressed sans hearing protection no longer left my ears ringing with this heavier buffer, and a couple of my shooting buddies also noted that the gun seemed quieter than usual (using my usual S&B 140gr subsonic ammo).

I have to get my hands on another set of tungsten weights so that I can "before/after" contrast an H3 buffer with my custom one using a sound meter.

I realize that my Radio Shack meter is not a "proper"/scientific test, but believe it is at least a bit better than "well, my ears didn't ring afterwards...".

Though, I'm also not guaranteeing DB numbers based on it either.

I also did up another one (this time in 304SS - what a bitch!) so I could give it to a buddy with an RDIAS and see what sort of rate reduction it would give. I should have a chance to test that in a couple weeks.

It does not tell you the dB ratings but I use Audacity to compare. You can record one series of shots then record another series of shots. Then you can slow them down to take a look at how they compare between them. This is what I used to figure out IMR 4227 is the best powder for my setup using my silencer.

[sillycon]

I finally got the proper tungsten weights late last week. I need to source a urethane "plug" to go in the end of the SS buffer and then I'll give it a whirl (the ledloy buffer is off for testing with my associate with the RDIAS).

[Joker31D]

I use an 11oz Slash's buffers stainless buffer and a Wolff XH spring, the sound is quieter than my spikes buffer and a Tubbs spring, I use it in my 6.5 Grendel that ate 3 buffers prior to the change. Heavy loads with 129gr bullets were killing them, recoil was stiff, now its pleasant but weird compared to my standard 5.56 rifles with regular buffers. I have a video but my ftp doesnt allow video files.

Source for buffer tips, better than stock style ones
http://www.buffertech.com/AR-15-Buffer-P75.aspx