If the gun is in spec, it will work with mags that are in spec (G.I.). If the gun is out of spec, or the mags are out of spec, it's usually the case that a happy combination of gun and mag can be found. I'm always leery of mags that toss the controlled-round feed of the 1911 in favor of something "better" (different). I have had good performance from my "timed release" McCormick mags, but am now firmly aboard the "hybrid" feedlip and "bullnose" follower bandwagon of Check-Mate Industries. Check-Mate has been a major player in the 1911 mag business for years, making "factory" mags for Colt, Kimber, Nighthawk Custom, and probably others. They make tubes and other components for other magazine makers, as well. Their hybrid feedlip, which combines elements of both the original tapered, and newer timed-release designs, combined with the stable, metal bullnose follower (skirts front and rear, to ensure it won't tilt in the tube), is the best mag of its kind. Their flush-fit 8-rounder is the only "8 into 7" mag that I use anymore and I've found their extended-tube 8-rounder to be better designed, and at least as well built as the Tripp or ETM.