American Precision Arms Little Bastard Gen 1 Muzzle Brake 5/8x24. they needed a smaller platform for rifles that couldn't handle a large brake. The LB can be turned down to .850" diameter to blend completely as if it were an integral part of the barrel on a non-magnum cartridge. Magnum cartridges should not be turned down. The brake should be left 1.0" in diameter and chamfered on the end to blend into the barrel. All of the require installation by a competent gunsmith. By properly fitting this brake you can achieve a perfect seamless fit on your rifle as well as perfect coaxial bore alignment. Please see the video for further information. Specifications for American Precision Arms Little Bastard Muzzle Brake: Manufacturer: American Precision Arms Color: Stainless Finish: Plaiin Fabric/Material: Stainless Steel Threads per Inch: 5/8x24 Model Generation: 1 Inner Diameter: 1 in Outer Diameter: 1 in Length: 2.225 in Weight: 3.9 oz Package Contents: American Precision Arms Little Bastard Muzzle Brake American Precision Arms G1L58GSS: Little Bastard Gen 1 Muzzle Brake 5/8x24