Lego minifig compatible Custom SI-Dan Toys M16A2.The M16A2 rifle was requested by the United States Marine Corps as a result of combat experience in Vietnam with the XM16E1 and M16A1. Modifications to the M16A2 were extensive. The Marines were the first branch of the U.S. Armed Forces to adopt it, in the early/mid-1980s, with the United States Army following suit in the late 1980s.