AR's under 1MOA...muzzle devices?

kymasabe · June 28, 2021, 06:18 AM

Expanding upon a current post about AR's that shoot sub-moa, a few people reported building their own or having bought guns a few years ago that turned out to be supremely accurate.
My question is...how much of that accuracy is affected by muzzle device choice? I've always been under the impression that a cheap, poorly milled A2 flash hider could cause accuracy problems so I tend to build my AR's with VG6 brakes/comps. But I can't honestly say I've done an accuracy test with different devices on same gun.
How much does a muzzle device affect accuracy?

stagpanther · June 28, 2021, 06:42 AM

I can't say for sure--but I believe that unless the baffles are so severely worn they are sending exhaust in erratic directions my guess is it won't make enough difference to throw the bullets successively to different places. An exception might be baffles that are ported pointing back to mitigate recoil--I've heard those can create turbulence as they wear out.

zukiphile · June 28, 2021, 08:36 AM

My guess would be that whether a muzzle device is finely machined has little bearing on accuracy, but the weight and length would allow a device to act like a tuner, effectively changing the weight and length of the barrel.

I've never found a way to predict how any specific device will influence accuracy other than to try it. I don't have a ton of experience in this, but I've only struck muzzle device gold a couple of times while it must be nearly a dozen times I've seen a degradation in accuracy.

I've a Dez Arms 20" pencil barrel with an old Levang linear comp that is amongst my most accurate centerfire ARs. For rimfire, I did once find a brake that both detectably reduced recoil and tightened groups a bit, but the reliable answer for those is a plain thread protector.

MarkCO · June 28, 2021, 10:29 AM

Minimal effect unless something is grossly wrong. The crown is more important than the muzzle device. I have seen POI shifts with comps that have poorly machined threads or point loads on the shoulder contacting the barrel.

Metal god · June 29, 2021, 11:04 AM

That NM rifle I posted the 10 shot sub moa group from in that other thread has a cheap A2 flash hider .

rickyrick · June 29, 2021, 02:16 PM

If you have a “whippy” barrel the flash hider mass can slow down the “whipping”
In other words, it can change the frequency of the barrel vibrations.

Probably not noticeable in an AR, but something else, with a pencil barrel and a piston and op-rod, it could possibly make the rifle more accurate, but it could be less accurate.

I’d definitely check your zero after changing anything at the muzzle.

June 28, 2021, 06:18 AM	#1
kymasabe Senior Member Join Date: June 10, 2005 Location: SW Florida Posts: 2,748	AR's under 1MOA...muzzle devices? Expanding upon a current post about AR's that shoot sub-moa, a few people reported building their own or having bought guns a few years ago that turned out to be supremely accurate. My question is...how much of that accuracy is affected by muzzle device choice? I've always been under the impression that a cheap, poorly milled A2 flash hider could cause accuracy problems so I tend to build my AR's with VG6 brakes/comps. But I can't honestly say I've done an accuracy test with different devices on same gun. How much does a muzzle device affect accuracy? __________________ God's creatures big and small, eat them one, eat them all.

June 28, 2021, 06:42 AM	#2
stagpanther Senior Member Join Date: March 2, 2014 Posts: 12,973	I can't say for sure--but I believe that unless the baffles are so severely worn they are sending exhaust in erratic directions my guess is it won't make enough difference to throw the bullets successively to different places. An exception might be baffles that are ported pointing back to mitigate recoil--I've heard those can create turbulence as they wear out. __________________ "Everyone speaks gun."--Robert O'Neill *I am NOT an expert--I do not have any formal experience or certification in firearms use or testing; use any information I post at your own risk!*

June 28, 2021, 08:36 AM	#3
zukiphile Senior Member Join Date: December 13, 2005 Posts: 4,578	My guess would be that whether a muzzle device is finely machined has little bearing on accuracy, but the weight and length would allow a device to act like a tuner, effectively changing the weight and length of the barrel. I've never found a way to predict how any specific device will influence accuracy other than to try it. I don't have a ton of experience in this, but I've only struck muzzle device gold a couple of times while it must be nearly a dozen times I've seen a degradation in accuracy. I've a Dez Arms 20" pencil barrel with an old Levang linear comp that is amongst my most accurate centerfire ARs. For rimfire, I did once find a brake that both detectably reduced recoil and tightened groups a bit, but the reliable answer for those is a plain thread protector. __________________ http://www.npboards.com/index.php

June 28, 2021, 10:29 AM	#4
MarkCO Senior Member Join Date: October 22, 1998 Location: Colorado, USA Posts: 4,362	Minimal effect unless something is grossly wrong. The crown is more important than the muzzle device. I have seen POI shifts with comps that have poorly machined threads or point loads on the shoulder contacting the barrel. __________________ Good Shooting, MarkCO www.CarbonArms.us

June 29, 2021, 11:04 AM	#5
Metal god Senior Member Join Date: April 10, 2012 Location: San Diego CA Posts: 7,135	That NM rifle I posted the 10 shot sub moa group from in that other thread has a cheap A2 flash hider . __________________ If Jesus had a gun , he'd probably still be alive ! I almost always write my posts regardless of content in a jovial manor and intent . If that's not how you took it , please try again .

June 29, 2021, 02:16 PM	#6
rickyrick Senior Member Join Date: March 15, 2010 Posts: 8,388	If you have a “whippy” barrel the flash hider mass can slow down the “whipping” In other words, it can change the frequency of the barrel vibrations. Probably not noticeable in an AR, but something else, with a pencil barrel and a piston and op-rod, it could possibly make the rifle more accurate, but it could be less accurate. I’d definitely check your zero after changing anything at the muzzle.