I don't own a Beretta 92, and will preface anything I say about the M9 by noting that civilian Beretta shooters seem to generally have very good luck with the weapon and most will never see a locking block failure, in much the same way that most Glock .40 cal shooters will never see a kB, etc. Can happen, odds are that it won't unless you really push the Beretta.
Disclaimer aside, however, with military issue M9s I've seen plenty of broken locking blocks during relatively intensive flat range work. At my unit if we put 50 guys on the firing line for a week, we probably break 3-5 locking blocks. Generally I'm not sure on the round counts involved, but in two cases I know the blocks failed after less than 2000 rounds. Not a real confidence builder in the weapon, even if the amount of use grossly exceeds what anyone would ever actually do in combat.
I personally suspect that an exclusive diet of M882 9mm ammo, which is loaded to something near +P levels, has something to do with the poor performance I see. Some cases may also be very high round count guns or blocks, but it happens to frequently too be a catchall explanation in my opinion. Could be the number of rounds per day on the range, as well, I suppose.
Anyway, if I, personally, owned a Beretta 92, I don't think I'd run any hot loads throug it on the practice range, but would not have any reservations about shooting +P defensive loads in a real world situation. That's just me, however, and YMMV.
Edited to fix spelling and grammar errors.