Put about 100 rds through my brand new M&P 9 PC Shield with no issues. I did clean and oil (7 oiling spots per the manual) prior to going to the range. The only issue I had was sore thumbs from loading the magazines- those are some heavy duty springs! Getting that 7th and 8th rd into the new magazines was a chore at first. I also noticed that the barrel around the ports tends to get really dirty/gritty, so be sure to clean those religiously.