My series 70 Colt 45 is jamming when it is feeding a round. I replaced the clip. I' ve tried different ammo. I' ve cleaned it. Recoil spring feels fine (I guess). The chamber looks rough. It' s not pitted with rust, but it looks like it' s coated in crud. If soaking the barrel in bore cleaner does not help, should I try polishing the chamber? I' ve never tried it before. I' ve been scrubbing the chamber with a bore brush and it' s not helping. Is the tolerance on the chamber so critical that I would not want to try polishing it myself? Specific suggestions would be greatly appreciated as I hate to have a gunsmith fix my toys![:@]

Jake