The American Model 45A Automatic Rifle Was Almost Forgotten It's essentially a hybrid battle rifle/light machine gun. Here's What You Need to Remember: Today, bullpup style rifles are used by the militaries of Great Britain, France, China and Israel but the radical design hasn't been widely used by the U.S. military. However, a weapon based on a similar platform was produced and briefly tested at the end of World War II. As part of the U.S. Army’s Next Generation Squad Weapons (NGSW), which will replace both the M4 Carbine and M249 SAW, one option is a rifle that features a “bullpup” configuration from General Dynamics. This layout places the magazine in the stock behind the pistol group—which reduces the length of the weapon but could require some additional training for soldiers used to the legacy systems.