The Heckler & Koch G3 is a select-fire battle rifle chambered in 7.62×51mm NATO developed in the 1950s by the West German firearms manufacturer Heckler & Koch, in collaboration with the Spanish state-owned firearms manufacturer CETME. The G3 was the service rifle of the West German Bundeswehr until it was replaced by the Heckler & Koch G36 in the 1990s after German reunification, and was adopted into service with numerous other countries.