I have only tried the one that came with mine, which works great, and the two argentena mags from CDNN I already complained about enough. Today I got two that are supposed to be mill issue, new in package. On the bottom is stamped 19200 next line ASSY 5508694, next line MFR. 1M292. I opened one and tried it, just like the CDNN cheapos it had to be pried out. Could it be the gun? I am sure I can fit it by filing on the mag catch slot. This mag looks identicle to the one that came with the gun except that one only says Colt, next line .45 AUTO. TIA.