Hey guys new to forum. Trying to make a decision on this 686 but what to know what could be causing these wear marks as I have never seen them like this before in this location any ideas of what could be going on?
It looks like marks from when the yoke was fitted to the frame. I see it was serviced for the hammer nose bushing ("M" stamp), so I wouldn't be too concerned.
If everything else seems good and the price is right, go for it!
As others said, fitting marks. I've seen a Model 60 no dash that's just like this.
Part of the hand-fitting/gunsmithing back in the day was simply that parts were manufactured to less repeatable tolerances. You can generally remove a little material if parts are made slightly oversized.
Welcome to the S&W Forums. Looks like fitting marks to me. S&W's are assembly line produced items, so it's not unusual to find machine or file marks and sometimes less than ideal fit, finish, and tolerances.