Gunsmithing Q: Brake vs bore diameter, how close is too close?

[n00g7]

Brake bore is approx .275 in diameter (A419 6mm hellfire).
Barrel is 25 Cal (so .257).

That leaves about a .017-.018 difference.

Given the 6mm stated application, the MFG expected difference is ~.031.

I suspect the MFG allowance is on the high side to afford a relatively large margin of error, but is .017/.018 cutting it too close?

 

[Mordamer]

I believe that is cutting it too close. The risk is high and the reward is nill. My advice is to have the brake bored out, sell it and buy a 6.5mm brake, or find some to trade it for a 6.5mm brake.

 

[flyer]

If it is perfectly centered and aligned the way it should be, that 0.009" on each side is an awful lot for a bullet to yaw in the 2-3" of brake.

If I could confirm the alignment, I think I would try it. Worst case you would shave your jacket a bit and get poor accuracy.

A nice straight piece of 1/4" brass rod would probably tell you what you need to know about alignment if you know what you are doing.

 

[Raufoss]

I run a 6mm Hellfire on my 25 creed. You have more than enough clearance

 

[n00g7]

If it is perfectly centered and aligned the way it should be, that 0.009" on each side is an awful lot for a bullet to yaw in the 2-3" of brake.

That was my thought, just verify that nothing is off somewhere.

I run a 6mm Hellfire on my 25 creed. You have more than enough clearance

Now I know who to blame if it doesn’t work.