How many rounds to break in a new pistol? I have a S&W Sigma 9mm, 1 light strike and 2 fail to feed in about the first 60 rounds. The next 75 went fine. I fired a mix of Federal 115 JHP's, Remington 115 JHP's, Winchester white box 115 FMJ and American Eagle 147 flat points. Like a dufuss I'm not sure which failed and I'll make note next time. This was the first I have fired a gun in about 30 years and I was exicted like a 12 year old kid with a 22 bolt action!