The G36, in severely modified form, was used as a "kinetic energy" part of the now-cancelled US XM-29 OICW weapon and it also served as a base for XM8 assault rifle (also cancelled). Technical description. From the technical point of view, the G36 is a radical departure from all the previous HK rifles, based on the proven G3 roller-delayed system. The G36 is a conventional gas operated, selective fire rifle, made from most modern materials and using most modern technologies.