The Impact will give you a crisp, clean, 3 pound break and will drop in to all Mil-Spec ARs.All components are captive in the lightweight, aluminum alloy housing. Hammer is wire-EDM machined from S7 tool steel that combines hardness to resist wear with superior impact resistance to withstand heavy use without chipping or breaking. Other components are EDM cut from A2 tool steel, then heat treated to Rc 56-60 for long service life.Installs using your rifles original hammer/trigger pins, Timney’s proprietary design eliminates pin walkout.