Snail Drum Mag

Years ago my father passed on to me what I now know as a Snail Drum Mag and a 1914 DMW Artillery Luger. The Luger is in 9mm. When I tried to load the Snail Drum Mag with 9mm ammo it seems as if it is too long and will not load into the mag. What do I have? and is it of any value?