I bought an old JC Higgins model 60 twelve gauge 2 3/4" full choke shotgun the other day. I am pretty sure it was made by High Standard in the 50's. My question is can I shoot slugs out of this gun being that it is a full choke with no screw in choke that can be changed? For that matter, can I shoot steel shot through this gun? I am leaning towards no for sure on the steel shot but am hoping for a yes on the slugs. I also think any magnum rounds are a no-no with thus gun as well? Any help would be great. Thanks.