Gunsmithing How critical is brake dia. exit hole?

[Wannashootit]

New barrel has been shipped for my 7-08, and I want to have it threaded for a brake (now)/can (down the road).

In selecting a brake, how critical is the exit dia.?

Does an oversize hole (if I installed a .30 cal brake) affect accuracy and/or effectiveness?

I think I had read somewhere that the exit hole should be .04 over (meaning .324 in my case)?

Advice/suggestions appreciated. Barrel is .85 at muzzle...

 

[turbo54]

Re: How critical is brake dia. exit hole?

.020" over bullet diameter is the gold standard, but I don't think it makes much difference.

The TRG brake fits 308 and 338, and is very effective on both.

 

[Decoy]

Re: How critical is brake dia. exit hole?

The tighter the hole the more effective the comp will trap the gases.

In pistols we use .010" for a major load but need to increase it to .030" for minor loads since the bullet may bounce on the comp.

Rifles have a larger volume of gas to use so the tightness is not as much as a factor. Different comp designs may effect accuracy so try out a diameter and you can always increase the size of the exit hole later.

.020" is a good start.

 

[Willys46]

Re: How critical is brake dia. exit hole?

Heck I had a 308 break laying around and slapped it on a new 6-47 lapua. It works pretty well.

I have another 6-47 that I was shooting today side by side that has a proper break to bullet fit, I would be lying if I said there was a big difference. They both have little recoil. Let's say it works well enough I did not order another break.

Willys