Chris C
i have to diagree with Veral Smith as i have fire lapped many barrels pistol and rifle and find that not be the case if done correctly. in your case just start with the finest grit in that kit which would be the 600 grit. or you could pick up some 1200 grit compound. if fire lapping worries you then another way to go is JB Bore paste.have you shot any jacketed bulets in that pistol yet. if not try that. you have many options here.HTH
Rick