Just got back from the range and didn't even finish off a mag before my mag started to drop. I tried to use other mags and they did the same thing. I removed the mag catch and noticed that the little metal piece that locks the mag in place is worn. I tried calling S&W but they only run a weekday operation. I'm so mad. Hopefully I'll get it back really quick. I have about 1100 rds through it without a single problem until now. Can anyone tell me if you send back a Rev M will they do all the Rev N upgrades before they send it back?