Can anyone ID this gun and the ammo used for a museum?
My guess is circa 1920s-30s. Probably U.S. made, has vertical sliding wedge breech block. Probably single loaded, not belt or clip fed.
Large housing around the barrel has a large spring inside. Exposed portion of the barrel at the muzzle is knurled.
Is this for the 37 x 93mmR 1 pounder Hotchkiss, or the Navy Heavy 1 pounder cartridge, or perhaps something else?
Did not see anything similar in Bob Mellichamp’s superb book on 37mm Volume I that goes through 1913.