Guys, please let me try to make the question clear. I am asking whether internal MIM engagement surfaces can be polished for the purpose of action/trigger jobs.

A gunsmith at a gun store I frequent tells me "no", and the consensus here seems to be more or less in agreement with the gunsmith, i.e., it can be done, but not nearly as well as with the old forged parts. I don't recall the reason for the gunsmith's negative opinion, but I think he said the MIM surface might be damaged--don't hold me to that.

My question is in no way a slam of MIM parts or of polishing external MIM parts for aesthetic purposes.

Everyone here agrees that MIM parts can be polished to make them shiny, and Bullseye takes it a lot further.

The S&W-provided MIM FAQ (Sticky) on this board (and even on S&W's own web site FAQ) does not address the question. So, yesterday I sent an email to S&W. I'll post S&W's reply when I get it.