I have Wilson, Mecgar, and one Kimber mag. All are 8 round mags. I had some trouble with the Mecgars at first, the ones that came with the 1911, but replaced the springs and followers with Wilson springs and followers and they work fine now. No problems with the Wilsons or the Kimber so far. It could have been just the break in period. Also, it's 45 ACP. Don't know if there is any difference between the 9mm and 45 mags as far as reliability.