[Herb]

Never heard of such a thing. Many Lugers are particular about the brand of ammo you feed them as some are just a hair more powerful, or less powerful. Try changing brands. Also check the 'lips' on the magazine to insure that they are not 'pinched' or otherwise distorted. The magazine follower spring may also be a little week from age. Try the ammo thing first, if nothing helps get a 'death grip' on that thing and have fun.