Metalform made the Detonics "factory" mags, though it's my understanding that the mags made for Detonics USA were to their specs, and not the same as the Metalform-branded ones that can be had from Brownells and others. I have two of the Metalform-branded mags. The first one worked perfectly, until one day, it didn't. I bought a replacement, and that one is still working. I also use two Metalform 7-round 1911 mags as reloads. With Wolff + springs in them I've never had a problem, but when the springs get a bit fatigued, the gun starts to choke. My experiments with 8-round mags have been bad, but I have acquired some new mags, from Check-Mate and Certac, and will try those, too; the stronger springs of the extended-tube mags may be better able to keep up with the Detonics' cycle rate.