Why the Australian SAS Refused to Use U.S. Weapons in Vietnam — And Why It Worked In the equipment room at Nuidat in 1967, an American special forces adviser watched with confusion as an Australian SAS trooper inspected his weapon before a patrol. The rifle was a L1A1 self-loading rifle, a 7.62 mm battle rifle that the United States had abandoned three years earlier in favor of the M16. The American couldn't help himself. You know, we've got crates of M16s you guys can use, he offered. Lighter,