I was cleaning my SR22 today, which has had about 1,000 rounds through it. I realized that the tip of the firing pin and the part of the firing pin channel I could see had some black build up. I tried to remove the roll pin that holds the firing pin/bolt assembly in the slide by using a punch. I hit the punch multiple times with a hammer using a decent amount of force, but it didnt budge. Should I just leave it alone, or should I re-attempt to knock the pin out?