My personal break-in with a new handgun is:
- field strip, clean, light lubrication
- get 250 through. If I get any failures, I'm more forgiving the earlier they occur
- another 150 or more. If I have any failures after 250 rounds*, I won't trust my life to the weapon. Minimum expectation is 150 consecutive flawless rounds from 250-400.
I put > 600 through my PPQ and SR9c in the first month with each.
*failures attributed to the handgun, as opposed to something that is clearly ammunition related.
Currently Own: Beretta PX4 9mm, Glock 23 (Gen 4), Glock 19 (Gen 4) x2