The Heckler & Koch G36 (Gewehr 36) is an assault rifle designed in the early 1990s by German weapons manufacturer Heckler & Koch. It is chambered in 5.56×45mm NATO, and replaced the heavier G3 battle rifle chambered in 7.62×51mm. [1] . The G36 was accepted into service with the Bundeswehr in 1997. [2] .