If this just started after you installed the Pachmayer grips the channel in the grips that the slide release moves up and down may be binding and preventing it from moving freely. I would not do any dremmeling.
Field strip the pistol and lift up and down on the slide release. If it does not move freely, remove the grip and see if it moves freely. Put the factory grips back on and check movement. If it moves freely with the old grips and does not with the rubber Pachmayer, get a razor blade and clean the slot out, remove any flash or open it up a little until the slide release moves freely like it did with the factory grips.