I read/reviewed Bruce Canfield’s book - A COLLECTORS Guide to UNITED STATES COMBAT SHOTGUNS w/the purpose of finding clues to determine what the ‘USA’ in ‘USA-F’ stands for. The periods covered includes WWI through Vietnam. None of the combat shotguns has martial markings either as stock cartouches or markings on the shotgun frame with ‘USA’, as in the United States of America. Secondly, my Rochester Ordnance Depot (ROD) shotgun already has USA stamped on the top of the left barrel. Third, it would be redundant to repeat it again under the barrel. The U S military is steeped in tradition, so it seems clear that it would not abandon tradition and change their practice of changing their martial markings from ‘U S’ to ‘USA’, as in the United States of America.

Therefore, I believe the ‘USA’ in USA-F stands for the U S Army. The HAC had a contract with the U S Army. We know that b/c shotguns were delivered to the (ROD).