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Muzzle brake killing groups

Andrew863

Gunny Sergeant
Full Member
Minuteman
Apr 21, 2018
539
212
37
Russellville KY
So last time at the range I took 2 new muzzle breaks to try. I tried the little bastard gen 3 and the area 419 hellfire. I tried to shoot a group with the LB and it was horrible. Last time with this load it was doing .25 to .5. It was around 1.5. I'm not going to freak out yet and I'm hoping I just had something loose and don't have to go to my old break or redo the load. But have any of you seen that happen?
 
Yup. Muzzle devices can change barrel harmonics enough that you'd need to work up a new load. Won't happen on all barrels, but it's common enough. How much torque you use to install the any muzzle device will affect it too.

First thing I'd do is confirm that the bore diameter is correct on the new muzzle device but chances are you'd need a new load.

Edited - Second thing is use the minimum amount of torque required to time the device. More torque than necessary tends to be detrimental.
 
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I've never had it happen on a bolt gun, but GOD DAMN does a surefire brake on my MK12 wreck my groups. Tried it back to back 3 times and shooting without the brake split the group size in half. Bare muzzle or suppressed.

MPA, Gen3 LB, 419 Sidewinder on my bolt guns all shoot great with the same load
 
I've never had it happen on a bolt gun, but GOD DAMN does a surefire brake on my MK12 wreck my groups. Tried it back to back 3 times and shooting without the brake split the group size in half. Bare muzzle or suppressed.

MPA, Gen3 LB, 419 Sidewinder on my bolt guns all shoot great with the same load
I really really hope it's a fluke or something else. But I had a friend have this happen on a ar10 but it was a 15.00 break off of eBay.
 
Yup. Muzzle devices can change barrel harmonics enough that you'd need to work up a new load. Won't happen on all barrels, but it's common enough. How much torque you use to install the any muzzle device will affect it too.

First thing I'd do is confirm that the bore diameter is correct on the new muzzle device but chances are you'd need a new load.
Yea I did check this. I have alignment tools for my supressors and they were both perfectly centered. Actually better then the one I took off.
 
Fwiw, I have found essentially no difference in group size with brake (gen-2 APA Little B*) on or off my .223 (Defiance / Bartlein / MPA / Timney). I did find that 6.5CM groups moved 1-2 tenths when the same brake came loose in the middle of a range day.

Good luck. This sounds like a weird situation.
 
I've had it happen once with a brake on one of my Remington 700's, it was a cheaper brake from Damage Industries, it was on sale, and I thought how bad could it be? Pretty bad as it turned out, even though it was mounted with shims and light torque, the accuracy was horrible, similar to yours, but removing the brake brought everything back to normal. I switched to a Badger Mini-FTE on that rifle and I haven't had any issues with accuracy since then. I was going to chuck that brake but ended up using it on my project HMR and crazy enough it's worked out fine, it's not the most efficient brake but it's not negatively hurting accuracy.

Like it was mentioned above, anytime you throw something on the end of a barrel it can effect things, sometimes negatively, sometimes positively.
 
I agree with many of the above. I have had barrels/loads that did not care if there was a brake or not, and I have had some that they did. I have never had one open up quite that much, but when I put a 6.5CM Criterion barrel on my old Savage worked up a load before my brake came in. I had it shooting about .5. I got an APA Lil B and the groups opened up to about 1 inch. I went back to work up another load and ended up .2 gr more powder and it was back to a .5.
 
Bad thing is I have to work all this weekend so I have to have this in the back of my mind till I get to try it again. I'm sure it will group fine and I had the break loose or something. But worse case I'll toss the old break back on and shoot this comp coming up and then tweak the load to get my groups back. I think I have decided to run the the hellfire, so as soon as I can post sell adds ill toss the little bastard up for sale.
 
I helped my high school bet friend assemble components to have the PWS at Quantico build a rifle for him before he retired from the Corps. One item I got him was an Area419 Hellfire brake for the end of the Krieger 1:10" 4-groove heavy Palma.
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When they test-fired in the sled, it consistently shot sub-1/2moa bare-muzzle and about 3/4moa with the brake regardless of ammo (LR, FGMM, M852). It happens. I actually tried a Hellfire on my TacOps Lima51 (22"). It didn't like the brake either.
My 26.5" Krieger barreled 300wm likes the Hellfire, as does my AIAX with 22" 308 and 24" 260 barrels. Mega Maten gas gun with 20" Proof 308 and 22" 6.5CM uppers like Hellfires also. Why does this happen? Harmonics? I dunno. I just figure I'll run 'em with a brake if it helps me spot impact without affecting accuracy. If it hurts accuracy enough to make me spot more misses than impacts, then I won't use it.
 
Yea it wild, I had a 30 dollar break off eBay and shot .262 groups. Works case it will have to do even though it it's not as effective for recoil.
 
Assuming you brake is mounted with a crush washer, the brake will time out to a specific length on the barrel. That length is pretty likely wthe wrong length for the resulting barrel harmonics, given the group size.

Remove the brake, and add a brake timing nut. A crush washer is no longer needed, too.

That way you can time your brake while increasing or decreasing the brake length along the barrel. That will permit the brake to be used as a harmonic tuner, and may even make it unnecessary to redevelop the load.

Greg