I had a revelation. I tried the much praised Wilson mags in another gun, since they seem to work well in my Baer Premier II (and McCormicks don't), and noted that the Wilsons didn1t kick the slide stop fully up into the notch on the slide on the other gun. The McCormick Power Mags and my Ed Browns make the stop fully engage in both guns, when the slide locks back on an empty mag (dry practice, not live fire). What the heck? I also noted that the slide stop is just starting to peen the corner of the slide stop notch on my Baer Premier II, because the slide stop is only catching the corner of the notch, not fully engaging. Could it be that the springs in the Wilsons aren1t strong enough? The McCormick Power Mags seem to work great, so I'm anxious to see their reliablity with live ammo. I'm also going to call Wilson, and find out what the the story is. They don't make the slide stop fully engage in TWO of my guns... doesn1t seem like a coincidence. I'm beginning to like the Power Mags for more than just price. Would +10% springs help in the Wilsons? I'm gonna call them. Anyone here have a similar experience, or vote for the McCormicks?