So my first problem was cured and I've ordered the parts to replace the damaged ones. Now it says 22LR on the barrel. I have tried 22lr AND 22 shorts and for the life of me I cannot get the round into the cylinder. The head, copper or lead, seems to bind and scrape the sides when I try to insert the cartridge. Now I believe that the guns were first made in '41 and this one is stamped 66xxx as the serial number, so I imagine it was produced somewhere in the 40s. Have the size of the rounds changed since this gun was produced?