muzzle brake accuracy went sough

[chet]

I installed a muzzle brake on my 300 win mag. and accuracy went south, from around 7/8' at 200yds to 2' plus. clearance hole at where bullet exits is approx.plus .018-.020, but the web thickness at the end of the brake is approx 1/4' should this be a thinner web, the brake is about 2' long with a series of 9/32 dia holes, I really never heard a brake deteriorating accuracy. any tips to correct this problem.


Chet

 

[Preacher]

The 1/4 inch behind the exit hole is not a problem.
It should measure right at .328 for the best results..
Have you shot it with out the brake on ??
Can you see if the brake is marked from the bullet coming out ?0
Like you mentioned, accuracy usually don't fall off if it's dialed in perfectly....

 

[Rust]

Could be the bore of the brake is not exactly in line with the bore of the barrel. One way to check is to use a close fitting spud down the bore with the brake installed to see of the spud has the same clearance all the way around the bore of the brake. Other than that, try a different brake.

 

[RGRobinett]

Or, the brake may be 'acting' like a 'tuner', altering the barrel vibration - you may simply need to adjust the powder charge-weight to recover the former grouping ability - that is, to get onto the newly established 'node'. RG

 

[squirrelduster]

The bore of the muzzle brake should be a minimum of .320 and a max of about .340 for best accuracy.
From my experiments it seems that the best is usually around .030 larger than the bore. The web size shouldn't matter. I haven't played with that so I don't know the effect for certain.
RG is correct about the tuner comment. If the barrel is a lighter weight model then the extra weight will change the barrel vibrations. You will probably need to change the load to match the new barrel harmonics.
The most important thing that I have noticed is the bore diameter. If you go above .040 over bore diameter you will start to reduce the recoil reduction.
One other note is that the brake will change the recoil pattern of the rifle and if you have any scope or mount issues it will amplify the problem. I actually sheared off two sets of Leupold mounts after I installed a brake. I needed to go to Warne mounts and bases.
Let us know what you find out.

 

[NateHaler]

I installed a muzzle brake on my 300 win mag. and accuracy went south, from around 7/8' at 200yds to 2' plus.I really never heard a brake deteriorating accuracy.

A brake will certainly do nothing to improve accuracy. I hate the damn, noisy things.

 

[chet]

I just got back from he shop, the hole measures .330 and it is concentric with the bore, I made a step pin, .301 dia x .327 and there are no issues with clearance, it is concentric, when I made the brake, I set up the barrel with a pilot and I indicated it in both ways to be concentric with the bore and ran the indicator down the pin about 1 1/2' and adjusted the rear spider accordingly, then I already had a 1/4 hole in the end of the brake, I installed it and bored it out, it is dead nuts. maybe it is me, just not used to shooting this rifle I had stored for 3 yrs, coming off of a 6bR maybe I need to get the hang of these larger calibers again. I hope it's me but I will shoot it again to make certain!


chet