Thanks A!A. A friend with a Cobra just told me his does the same thing. Apparently there is a rivet in the hammer, and the firing pin moves around it slightly. Think I wold have noiticed this at the get-go considering how much time I've stared at it though the magnifying glass! /forums/images/graemlins/grin.gif
The Colt hammer mounted firing pins MUST be slightly loose.
This allows the pin to align itself with the firing pin hole in the frame.
For a short time back in the 1960's, the small framed Colt's had roll pins in the hammer to retain the firing pin.
Needles to say, this was ugly and people hated it. Colt soon went back to a solid pin, polished to make it hard to detect.
For some reason, rim fire Colt's firing pins are solidly fixed and should not move.