357 trigger problem help

[YoteAssasin]

so i have completely disassembled this gun (monson mass mod 15 ser # 301xxx) and after polishing the internals the trigger is still hanging up after it is fired. so just now i noticed that the cylinder advancing hand appears very worn like it has 2 edges or it was fitted but here is what i have reasoned the trigger is hanging up at the very end of the stroke and i thought the transfer bar was snaging some thing so i polished it and all of the metal it touches and smothed out the cyinder retaining ball screew and it still did it so i assemdled the gun without the hand and the problem went away so i now i know it is draging i need to know how much metal i can take off the bottom side of it. to reduce the drag coming back across the advancing star  thank you and is this a common problem cause i realy like this gun and  i hate having to deal with this crap