Muzzle Brake Bore Diameter

[hbjones]

What is general rule for clearances in muzzle brakes in relation to bore bullet diameter. Would a muzzle brake reamed for a 30 cal not be as effective if used on a .284 with the extra clearance ?

Thanks

 

[Preacher]

Generally you'll want .020 over bullet diameter clearance for the exit..
That seems to be the best for accuracy.
Much more than that and it can get squirrelly at best..

 

[hbjones]

Preacher,

For a 7mm (.284) you would use a .304 opening. Are you reaming the bore on the end of the muzzle while in the lathe or setting up a sperate threaded mandral for the reaming process. The only reamers that i have close to that size .312. I think that will use a boring bar to get the exact .020.

Thanks

 

[gunsandgunsmithing]

What is general rule for clearances in muzzle brakes in relation to bore bullet diameter. Would a muzzle brake reamed for a 30 cal not be as effective if used on a .284 with the extra clearance ?

Thanks

.020" is the general rule, and you are correct... It will make a brake considerably less effective to have the hole much bigger than it needs to be.--Mike

 

[rbertalotto]

And the hole should be bored using a small boring bar while still attached to the barrel that is in the lathe and indexed perfectly. In this way the exit hole will line up with the barrel's bore perfectly.

 

[hbjones]

Thanks for the responses.

I now have a brake that has a .340 ( don't ask) bore to experiment with. I am going to fit another brake with a .304 bore and compare. These will be on a 7mm Rem mag shooting 180 grain Berger VLD. I will post results.

Thanks
Britt

 

[CaptainMal]

Wanna hear about those results. Been wondering about this as I'm thinking of using a 25 Holland brake on another barrel in 6MM.