Trying to identify a canvas holster that looks nearly identical to the M1 Carbine Holster (by Protection Products Co., 1943) that I have. The main difference is that the unidentified one will only fit a weapon slightly longer than an M1 carbine stock. It is made of deep olive green canvas, has slightly smaller rivets, black leather reinforcement around the slot for the operating rod handle, & is marked with a large "U.S."; no other markings. The only weapon I can think of that would fit is the Iver Johnson Enforcer 30 Carbine, but can find no picture or description of any holster for it. What do you think I have? Thanks!