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 CALIPER or MICROMETER measure the diameter of the barrel at the muzzle and 1.5" from the muzzle (1.625" for our Custom Threaded Adapter).
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, Ruger American clamp-on brakes or Mosin Nagant brake. We have test barrels here at the shop for these rifles.