Thread: Muzzle Brake Dimension/ Clearance Question .

0.6 mm above real projectile diameter at minimum….provided everything is properly lined up.
But even if it is 1mm or 1.2mm above hole diameter, usually a good brake will still be very effective.

As a reminder , a 7.62 (.30 cal ) is 7.82mm in diameter. So a clearance hole of 8.4mm would be the minimum suitable.