Mec Gar is all I use on 1911's. The failure to feed your experiencing has a lot to do with the follower. Most 1911 magazine followers have no support on the front thus causing the front of the bullet to tip donward and as the slide returns to battery it pushes the bullet down on the ramp, thus jamming.
Mec gar mags followers has a support on the front which prevents the downward motion of the bullet tip.
Some of the causes of jams on the 1911 are: week mag spring, bad follower, ramp not smooth, dirty ramp from shooting lead bullets, bullet type