muzzle brake

bill larson said:
i use .020"
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I use the same thing. The clearance size doesn't make much difference as long as it's centered. I built a brake with .002" clearance once for a .22 PPCXL that I had built. Accuracy with or without the brake was excellent. The brake was made like a Vais. A rule of thumb is the larger the exit hole is in relation to the bullet diameter, the less effective the brake becomes. But, I sure haven't seen anything wrong with using .020" over bullet diameter. By the way, the .22 PPCXL was a .22 PPC roughing reamer run into headspace for a .220 Swift and the neck and throat cut with a .222 Remington .246" neck with .060" freebore. I was shooting 52 gr Berger's out of a 14 twist Douglas air gauged barrel at about 4000 fps. It was death on coyotes, but the semi rim caused feeding problems.
 
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It really depends on how the brake is made and how it is fitted.. My preferred method is to finial bore the brake bore dia when it's being fitted to the barrel. I clock up the bore with a long stylus indicator, thread and index for the brake and then finial bore with the brake screwed on the barrel. This ensures perfect alignment with the bore. With this method you can go right down to 0.002 as Mike as said.. However i normally make them 0.010 for cals up to .264 and 0.020 for anything over .264..

If your just threading the barrel between centers then i would give 0.020 MINIMUM clearance..

Cheers
Leeroy
 
Muzzle brake clearance..

A few years ago there was a study done and the average accuracy was best at .020" over bore diameter. Doing the math this is just over .010" clearance. Accuracy deninished on tighter or looser brakes.
Nat Lambeth
 
Rflshootr said:
ok now, does a muzzle break with no holes on the bottom screw up the gas flow and cause accuracy problems?
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No it doesn't. I've shot them for years on varmint rifles. The bullet is gone before the gases have an affect on the barrel.
I normally have .010"-.015" on a side on my brakes.
Dave
 
Rflshootr said:
ok now, does a muzzle break with no holes on the bottom screw up the gas flow and cause accuracy problems?
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I'm with Dave but I will add that IMO it is possible to screw up the design of a muzzle brake by using to big an "expansion chamber" which allows gas to pass the bullet. IMO if this happens it don't matter WHERE the holes are :)

But a properly designed brake does bleed off behind the bullet.

al
 
alinwa said:
I'm with Dave but I will add that IMO it is possible to screw up the design of a muzzle brake by using to big an "expansion chamber" which allows gas to pass the bullet. IMO if this happens it don't matter WHERE the holes are :)

But a properly designed brake does bleed off behind the bullet.

al
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al's right. About an 1 3/8" maybe 1 1/2" is all you can get away with for an expansion chamber type brake. That's the style I've made for years and keep the internal chamber length around 1 1/4".

Dave
 
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