What I have is a Frankengun, the lower is an early (1898-99) Large Ring Hammer Bolo, with the original short throw safety. The upper looks like a 1920's Prussian contract, 3.5" barrel, 500 Meter tangent sight, but in .30 Mauser. Rifling is intact but worn. Upper has been refinished and is missing all but a few proof marks, no full serial and no caliber stamp.
Link Removed