Muzzle brake clearance question

[1jonathan1994]

How much clearance do I need between a muzzle brake and the bullets?
The brake that came with my MPA 6.5 will pass a 308 bullet and I want to shoot a 7mm barrel.
I'll check with a caliper this weekend.

 

[Steel head]

I use a 30 caliber brake for my 7mm

My 6.5 brake definitely won’t pass a 308 bullet.

 

[b6graham]

Is it a 30cal brake?

Should say right on it

 

[raz175]

.020-.030 over bullet diameter is the standard for muzzle brakes.

 

[1jonathan1994]

.345 hole on a 6.5 creedmoor.
.345 - .284 = .061 so I'm good

 

[n00g7]

The Area 419 brakes I have in 6 and 6.5mm I bought to try for a 25 creedmoor are about .030 over iirc. I’m using the 6.5 as the 6mm is a little close for comfort with only .017 clearance on a QD brake.

The ZRO delta I have marked 6.5 and which I’m using on a 6mm has a lot more clearance and still seems effective. Going with a next size up has pretty minimal affect as tested as well.

 

[1jonathan1994]

The Area 419 brakes I have in 6 and 6.5mm I bought to try for a 25 creedmoor are about .030 over iirc. I’m using the 6.5 as the 6mm is a little close for comfort with only .017 clearance on a QD brake.

The ZRO delta I have marked 6.5 and which I’m using on a 6mm has a lot more clearance and still seems effective. Going with a next size up has pretty minimal affect as tested as well.

I'm not trying to get minimal clearance. Just trying to use what I already have.

 

[flyer1a]

We want a brake to have at least .030, and as our brakes get larger in caliber, the clearance increases. Not only is it a safety issue, we have seen it as an accuracy issue. We have shot 6.5s through brakes bored to about .270 (on the lathe while installed as to be confident everything is square and will clear) and rifles just don't like it. Once you get up to about 25 those problems seem to go away, so our brakes will always have more than that.