Muzzle break issue

[spudgun]

Was out sighting in a new scope with a T/C, 308 cal. At 100 yds I was shooting all over the target. Checked my scope mounts, they were good. After 15 shots I was about to give up. I decided to take off the muzzle break that I had on the barrel. My next 3 shots were grouped under a $.25 coin. I then put the break back on and was shooing 2 inches high and erratic.
I didn't think a muzzle break would effect the accuracy but in my case it did.

Anyone else notice this?

 

[DngBat7]

Just curious who is the maker of the brake? It also needs to be professionally bored out .020 over bullet diameter. (A gunsmith on here can certainly correct me). But I would imagine a cheap brake not bored correctly may cause this?

 

[rammac]

Nope, never had that problem with my brakes but then mine are properly centered and I don't get bullet strikes.

 

[Fred B.]

Added weight will change barrel harmonics. Try different ammo or load.

 

[ebb]

If it was loose it will certainly effect accuracy.

 

[fyrewall]

I once had a brake problem on a .375 H&H. At first it was installed on a recent make M70 factory barrel. Without the brake accuracy was barely acceptable, with it was terrible, about 2 foot groups at 300 yards. I had it re-barreled, scrapped the old barrel and reinstalled the same muzzle brake - 3-4 inch groups at 300, near same impact, with or without brake, without scope adjust. I gave up trying to figure out the reason why the brake did not work on the first barrel. Everything was to spec on both installs, measurements centered, looked good. It was a Vais brake - the kind with all those holes. Apparently it only takes a tiny amount of misalignment to screw things up. I would suggest chopping a half inch off the front of the barrel and retreading.

 

[theallcineyes]

Are you using factory loads or hand loads?
The brake changes the harmonics of the barrel, and in some cases the muzzle velocity. this can cause a group to open or close up depending on the rifle and load. this is especially true if a load was worked up in a rifle without a brake on.

 

[Texas10]

Erratic groups could simply be that the brake is acting like a tuner and a different load might shoot better. However, it you're seeing really bad flyers, I'd suggest having a close look at the brake as you might be getting bullet strikes.

 

[spudgun]

Thanks guys. I can except the fact that it may change the harmonics of the barrel. No it was not loose, no it does not have bullet strikes, no I am not going to cut off the barrel and re thread. I was just wondering about the small holes to help reduce the muzzle rise effecting the accuracy. Again, thanks for your help.

 

[eric32]

Try a muzzle brake with a jam nut, might solve an alignment issue but it, could be your threads are off center from the bore. Hence the erratic groups.

 

[Kurz]

I then put the break back on and was shooing 2 inches high and erratic.
I didn't think a muzzle break would effect the accuracy but in my case it did.

When this situation occurs the brake is not shouldered up true to the bore, it's off several thousandths. Check the shoulder on the barrel by indication and then check the shoulder on the brake. Correct the one or both that are off.

 

[MOA]

I just rethreaded a factory barrel that was off by .020 of center. Had horrible groups with brake on. Good groups with no break. I'm just a machinist not a gun smith.