[m&p45acp10+1]

You should be ok. Do not seat shorter than the minimum number for the load. Seating too short especialy in high pressure small cased rounds like 9 mm can spike pressure greatly.

Ok that said if they are hanging on the feed ramp going from the magazine, and the gun hangs kind of open. Chances are the round is too short and you can seat longer up to the lenght that your magazine will handle. If the slide does not go into full battery, and it hard to extract the round then that can be an either/or both scenario. Too long, then seat a couple of thousandths deeper. Not enough flare removed. If so then screw the seating die in 1/4 turn increments till the rounds chamber, and extract without gumming up the action, just be sure to back the seating stem out a tad when you do.