We have 3 main sizes of muzzle brakes to fit most barrels, Fat Bastard, Little Bastard, and Micro Bastard.
The Fat Bastard for barrels ranging from .850" to 1.125". - Match & Heavy Barrels.
The Little Bastard for barrels ranging from .750" to 1.00". - Bull & Heavy Sporter.
The Micro Bastard for barrels ranging from ..600" to .750" - Light Sporter Weight.
The Gen 1series is meant to be installed by a competent gunsmith. The rear of the brake requires a chamfer to blend perfectly with your barrel. Additionally, the gunsmith will back bore the brake for perfect coaxial bore alignment. The end result is absolute mechanical & cosmetic perfection!
The Gen 2series just makes life simple. Its simple two-piece design does not require a professional installation if you have a barrel that's already threaded. For the competitive shooter that burns through barrels like toilet paper, he can now move the brake from barrel to barrel in about 30 seconds.
The Gen 3 series picks up the Gen 2 series and improves recoil reduction by adding an additional port but then goes a step further with turnable top ports to reduce muzzle rise.