For Clamp-On Muzzle Brakes we only need the caliber and Two Measurements in order to custom machine the muzzle brake to fit your rifle.
Using a DIAL CALIBER or MICROMETER measure the diameter of the barrel at the muzzle and 1.5" from the muzzle.
Please be as exact as possible to ensure we machine the correct diameter bore into your brake.
We do not need measurements for any of the threaded brakes, SKS Brake, or Mosin Nagant Brakes. We have test barrels here at the shop for these rifles.
For Clamp On Muzzle Brakes please type your barrel diameter at the muzzle as a 3 digit measurement (ex. .579) in the box on the product page. While we do re-cut mis measured brakes at no charge an accurate measurement will get you up and shooting quickly.