HK SL8-1 223 Rem Semi-Auto Rifle with 20 Inch Barrel for sale. Back by popular demand, the SL8 is an import-legal version of the G36 designed for precision shooting. It features a cold-hammer forged barrel with a recessed crown. The free-floating bull barrel is manufactured with the famous HK cannon grade steel. The G36/SL8 short-stroke gas piston, later featured in the HK416, ensures smooth, clean, reliable operation. The SL8 also features a short MIL-SPEC optics mount, match trigger, and an adjustable stock.