The Model 45A was a battle rifle/light machine gun developed by the United States Army in the Philippines in 1945. The weapon existed in prototype or mockup form, but never entered production. The rifle was sparsely documented until Tom Laemlein encountered a number of annotated photographs of the rifle in the archives of the United States Army Signal Corps.
The rifle was constructed in bullpup configuration, utilizing the magazine from the M1918 Browning Automatic Rifle. Rather than iron sights, it featured an integral scope. Its purpose is unclear, but it is alternately described as a "experimental .30 caliber LMG" or a "field expedient .30 cal."