Shot the CM for the first time a couple of months, and guess what? I had failures to feed the last round on two of my three mags. All three mags had been loaded since the last trip to the range, where all three mags functioned perfectly. It's hard to beleive that the springs would degrade that much in only a couple of months. I have two brand new mags to test, so we'll see if it is only the springs. Springs are cheap, but changing them every month? Yeah, springs are cheap - insurance.