Yes in my ignorance I bought pieces from a catalog and built this gun. The stainless action is not a T model, and adding the copolymer barrel, although fun to shoot, after about 150 rds. now misfires very often. Help!
I doubt anyone can diagnose the problem without more information or seeing the gun.
Actually, I suggest you get all the info you can on whether the cartridge rim is dented or not, whether the headspace is OK, etc. and then try on "The Smithy" forum.