Affect of flash hiders and muzzle brakes on AR accuracy and can I shoot the moon?

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BSA1

BSA1

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There is a lot of discussion about barel twist and bullet weight when it come to accuracy in the AR but I don't recall seeing information about the effect of flash hiders and muzzle brakes. I have three different 5.56 AR projects either in progress or planned with all three using different barrels.

Rifle project #1 is in progress. I am researching barrels and am pretty flexible at this point on what to choose. I am leaning towards 16" M-4 style. Mid-Length gas system. No firm decision on barrel twist. My other AR's have a 1 in 9" and the other is 1 in 7". Maybe 1 in 8" just so I can say it covered all the bases.

Rifle project #2 is more concrete. It is going to be a lighter weight using a 16" pencil barrel, carbine gas system and slick side upper receiver. Free float handguard. With a lightweight barrel I am wary of a heavy muzzle brake.

Rifle project #3 which is at least a year away is going to have a 20" barrel with the intention of using it for hunting. I may skip a flash hider or muzzle brake altogether.

I will shooting mainly 55 grain FMJ in projects 1 and 2 with occasional 62 ones.

As project gun #3 is going to be used for hunting it will have a 20" barrel and heavier bullets.

So three very different purposes which leads me to ask what the purposes of the various flash hiders and muzzle brakes and how they affect accuracy.

Oh as for the moon that will be a true long range shot.
 
If you are going for the most accuracy and a hunting rifle I would go with the fluted HB, 1:8 twist, target crown, and no muzzle device. The 1:8 is good for the heavier bullets and there's nothing gained in the 1:7.
You should get 1/2" or better groups with a barrel like that.
 
My carbine has a pencil barrel and it shoots quite well. It has a surefire flashhider, BUT it shoots equally well (just a couple inches lower at 100yd) when I ratchet on the surefire mini suppressor. I was leery at first, but no issues here!

The 458 socom has a shorter heavier barrel, but it shoots about 1 inch at 100 yards with or without the fat old direct thread bowers vers50 on the end. So again, no notable change except a lower poi.

I think most any brake or muzzle device will do just fine for practical shooting. I have shot long range out to 1000 yards on many rifles with brakes, flash hiders and suppressors. No trouble at all. Not bench rest shooting, but more prs style. I think the biggest thing to watch for is the quality of the thread job and the brake/mount installation.

I tend to shoot better for longer with a brake or suppressor simply because it makes the gun more friendly!
 
Actually did a test about your question.

8 different options were used - NOTHING attached to barrel to flash hiders, 2 port, 4 port, & and multiport brakes. Most affected accuracy and definitely affected POI.

Some POI shift was 20" - yes, some will not believe this...but...it did happen.

Some of the various bullet type/weights used also did not like certain muzzle devices....at all.

Because of this testing, I now purchase thread protectors.
 
dcloco said:
Actually did a test about your question.

8 different options were used - NOTHING attached to barrel to flash hiders, 2 port, 4 port, & and multiport brakes. Most affected accuracy and definitely affected POI.

Some POI shift was 20" - yes, some will not believe this...but...it did happen.

Some of the various bullet type/weights used also did not like certain muzzle devices....at all.

Because of this testing, I now purchase thread protectors.
Click to expand...
was that with high velocity round like 5.56 ? i would think a slower round woundnt
 
Last edited by a moderator:
info from a muzzle break site
http://www.muzzlebrakes.com/Faq.aspx
Q. Will my rifle lose any of its accuracy after the brake is installed?

A. No. A brake that is properly made and installed should never hurt the accuracy of a rifle. In many cases we get reports of improved accuracy. Some of this is due to the customer shooting better because of the reduced recoil. Accuracy is sometimes improved because of the way the muzzle brake diverts gases away from the bullet path.
Click to expand...
 
dcloco said:
Actually did a test about your question.

8 different options were used - NOTHING attached to barrel to flash hiders, 2 port, 4 port, & and multiport brakes. Most affected accuracy and definitely affected POI.

Some POI shift was 20" - yes, some will not believe this...but...it did happen.

Some of the various bullet type/weights used also did not like certain muzzle devices....at all.

Because of this testing, I now purchase thread protectors.
Click to expand...

Are you trying to tell us that POI at 100 yards was 20". I would have to argue that. I've been shooting for over 50 years so I'm no beginner and can't imagine a rifle that was in good condition changing POI 20". If you would explain how this could be using empirical evidence I would appreciate it. I'm pretty mechanically inclined so feel free to get technical.
 
He didn't state range, or anything else. If 100 yards, he is right about one thing, that some won't believe it. I would be one. I assume he meant some distance far beyond 100 yards.

Russellc
 
Being as the bullet has left the barrel by the time it interfaces with a brake....there's not much that can be affected so long as it doesn't strike a baffle which of course it shouldn't. Now...hanging that weight on the muzzle could obviously change the barrel harmonics and hurt or help the accuracy (think Browning BOSS) and it would be a crap-shoot as to what effect this would have. It wouldn't surprise me that 20" difference could be had especially if dealing with a thin and 'whippy' barrel.
 
RecoilRob said:
Being as the bullet has left the barrel by the time it interfaces with a brake....there's not much that can be affected so long as it doesn't strike a baffle which of course it shouldn't. Now...hanging that weight on the muzzle could obviously change the barrel harmonics and hurt or help the accuracy (think Browning BOSS) and it would be a crap-shoot as to what effect this would have. It wouldn't surprise me that 20" difference could be had especially if dealing with a thin and 'whippy' barrel.
Click to expand...

I am thinking mainly about how the weight will affect harmonics on a pencil barrel.

My theory is the weight will have less effect on stiffer barrels like M-4 and long 20".

We know that uneven crown effects accuracy. Screw on flash hiders and muzzle brakes do not seem to have the same degree of precision and in fact the ports especially on muzzle brakes are rather crude.
 
I've often thought that a brake that is not perfectly concentric with the bore should cause some instability due to disrupting the muzzle blast following the bullet out of the barrel and applying more force to one side of the bullet than the other and even partially destabilizing it. I'm not suprised that changing brakes would cause a change of poi and accuracy. I tried my AR with and without brake and couldn't tell the difference on that. I removed it now due to the offensive noise and put a flash hider on it. That's going away too as soon as I get a thread protector.
 
All the top 3 gun and Practical rifle competitors use a muzzle device, heck the bench rest guys use them. I was explained the dynamics on this a few years ago, I am a believer in them now.
 
If you are going for the most accuracy and a hunting rifle I would go with the fluted HB, 1:8 twist, target crown, and no muzzle device. The 1:8 is good for the heavier bullets and there's nothing gained in the 1:7.
You should get 1/2" or better groups with a barrel like that.
Click to expand...

There's a lot more to a 1/2" rifle than that barrel description.
 
I noticed quite an improvement on my 16" 5.56 stainless steel barrel, switching from standard A2 flash hider, to Thunder Technologies heartbrake, felt recoil was reduced and it is much quicker on target with followup shots. No noticed change in POI between the two different muzzle devices. This is a 1:8 twist chambered in 5.56, using 55 grain, and 64 grain bullets. right around 1 MOA at 100 yards, if that matters.
 
I had a really nice aluminum single chamber howitzer brake on my 20" AR and loved it. Very effective recoil reduction, the crosshairs barely moved from the target at 200 yards. Made follow up shots extremely fast. Then I was curious how loud it would be hunting so I took my muffs off and shot one round. I was rewarded with 2 painful ringing ears for a day. I took it off the same day.
 
Yes...20" POI from NO muzzle device and WITH muzzle device (4 different muzzle devices + nekid), using TEN different bullets at 200 yards.

40 gr VMax
52 gr HPBT
53 gr vmax
55 gr SP Winchester
55 gr SP Hornady
55 gr Vmax
55 gr FMJ
68 gr HPBT
77 gr Sierra
80 gr Sierra


Originally going to use 8 projectiles, ended up with 10.

This was shot from a bench, with bipod and rear sandbag.

A2, 3 prong, 2 port, 4 port, and nekid were the options on the end of the tomato stake.

This barrel does NOT like the FMJ's or one of the 55 gr SP's.
 
someguy2800 said:
I had a really nice aluminum single chamber howitzer brake on my 20" AR and loved it. Very effective recoil reduction, the crosshairs barely moved from the target at 200 yards. Made follow up shots extremely fast. Then I was curious how loud it would be hunting so I took my muffs off and shot one round. I was rewarded with 2 painful ringing ears for a day. I took it off the same day.
Click to expand...
dont yah hate that when ya get curious like that;)
 
I can wrap my head around a 20" POI at 200 yards considering all the different bullets used but that still seems like an awful lot of variation. Very informative.
 
It’s pretty easy to get an AR to shoot 1MOA groups with a decent freefloated barrel and trigger plus decent ammo. Getting better than that is where you’ll be spending the real money.

A decent* muzzle device isn't going to have a significant impact.

BSW

*The firebreathing dragon head flash enhancer, who knows?
 
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