Multi-port brake softens felt recoil and reduces muzzle rise. A single expansion chamber and 42 total ports, 21 on each side, angled 7Adeg forward, provide maximum recoil control. Gunsmithing required. Comes with a .220" (nominal) diameter exit hole that must be opened up to .020" larger than bullet diameter. Can be enlarged to allow bullets up to .44 caliber. Rear exterior of comp can be machined to conform to barrel. Mfg: Shrewd SPECS: 416 stainless steel (SS), satin finish. 2-5/8" (6.6cm) long.