The HK SL8 (SL8-1) is nothing more than the HK G36 assault rifle in civilian guise with semi-automatic fire. Both weapons are the product of Heckler & Koch, with the HK SL8 series entering the market in 1998 and continuing production as of this writing. By all accounts, the SL8 shares much commonality with its more powerful cousin and is a favorite sporting rifle around the world with some owners going to the extremes of modifying the base sport rifle to look like the G36. The SL8 was originally developed for use by German reservists as a comparable unit to the G36 as used by the German Army.
Taking the base G36 assault rifle model, Heckler & Koch modified the stock and grip with a fixed stock with integrated grip for the civilian market. The carrying handle and integrated optics are also removed in the civilian version though after-market sources are available that sell these as an add-on. Beyond that, the commercial SL8 (at least for sale in America) is also modified to not accept high-capacity magazines like that as found on the G36 assault rifle. Conversions by SL8 owners of this limitation is possible, however, though at the risk of violating the 1968 Gun Control Act.
At its core, the SL8 weighs in fully-loaded at 8.6 pounds and features a 20.80 inch barrel. The barrel itself i of a heavier type than that found on the G36, offering up better control and accuracy. A 10-round detachable polymer magazine of .233 Remington or 5.56x45mm NATO ammunition feeds the semi-automatic system that utilizes gas operation, a short stroke piston and a lug type rotary-locking bolt for the firing process. Iron sights are standard and adjustable with a detachable MIL-STD-1913 rail system offering up the ability to mount the G36 sighting system as a option.
The SL8 exists in other marketed (or soon-to-be) forms including the silenced SL9SD firing subsonic 7.62mm ammunition and the R8, featuring a bolt-action mechanism for sport shooting.