Mags not consistant

I have the black and a FDE one and they are not the same dimensions. The black mag barely fits in 5 of my 6 lowers, it works fine in my Sig M400 lower. The FDE drops free in almost all my lower except for my Spike's The Jack. I would recommend a spring upgrade as the last 2 rounds don't feed; i was only loading 22 rounds. In a limited market these are a decent choice but expect to have to put some time into fit and feed. The finish was being scratched off these mags within the first try. The new C-Products mags seemed to be of better quality than these and fed better in my guns because the come with the extra power springs. I was told you can replace the springs in the ASC with AK mag springs but I haven't tried.