Single expansion chamber and 42 total ports, 21 on each side, angled 7° forward, provide maximum recoil control. CNC machined for precise fit with very little finish work. Rear of comp can be tapered to conform to barrel. Bore exit hole must be opened up to .020" over bullet diameter. Mfg: Shrewd SPECS: Chrome Moly In-the-white or Stainless Steel, natural finish. 2" (5cm) long 1" O.D. 3 thread sizes: 5/8"-24.