In doing a quick mag change with M9....slide is back....drop empty mag....firmly insert loaded mag....slide goes forward to proper position....get sight picture....pull trigger.....oh crap!! I already told you the ending. The safety dropped down 3 times in 300 rds. following that sequence. The knurled tips feel a little looser than on my S9....but otherwise both guns have been flawless in thousands of rds. fired. More use of the S than M. Any ideas? Thanks