I think you are talking about the trigger spring retaining spring, you want to leave that alone. Install the grips and put lots of presure on the grip where the pin is. It should leave a mark. Then take a small drill bit about the size of the pin and drill a small shallow hole by spinning the drill between your themb and forefinger till it is deep enough for the pin to fit in. If you have your owners manual check the exploded view page and look for the pin number, then check it against the list to find out if it is the trigger spring pin.