I have two in my safe, but I don't know a lot about them. I do know the top opening lever model was made from 1938 to 1965. I believe that one is the one you have. The later version, with the side opening lever, was made from 1965 to 1972. The side opening lever model is called the 220L. I have a 12 gauge 220A and a 16 gauge 220L. Hope this helps a little.