I can't find much info on these guns. What I can find seems to indicated most of these guns had a brass frame, usually nickel plated. I'm guessing mine is iron, since it obviously isn't brass. Any help here would be greatly appreciated. I was warned to only shoot standard velocity shorts or CB caps in the gun. That makes sense to me, the breech lockup on these guns isn't exactly bank vault strong. I suspect even standard velocity rounds would eventually loosen up things. I plan to stick to CB caps, loaded in short cases, when I can find them. I did fire one round of high velocity to test things. Worked fine, and I'll call that a proof test. Lol !.