A couple of interesting points on that feeding. First, forget the nice pictures about the easy and gentle action of a 1911. Not true.
When the gun is fired, the slide comes back hard and slams into the recoil spring guide, which is backed by the frame. The slide does not lose its energy, it deposits much of it with the frame, which returns it so the slide bounces off the frame. The slide does not begin its return due to the spring since the spring takes time to recover, it begins its return due to that almost instantaneous bounce.
So the slide is moving very fast as it encounters the top round in the magazine. The magazine is designed so that the rim of the top round sits in the extractor groove of the next round and some pressure is required to get it moving. It is that slight delay that allows the round to rise along the breech face and under the extractor.
If the magazine is designed to minimize that resistance in a misguided effort to make feeding smoother, the fast moving slide will act like a baseball bat hitting a ball and kick the round free of the magazine and ahead before the extractor even reaches it. Meantime, the next round in the magazine is trying to move up under pressure from the magazine spring. It hits the jammed round and stops in the way of the slide. The slide hits it and stops, totally locking up the gun.
Since the extractor is not engaging the rim of either round, the usual "rack" won't work. The usual procedure is to lock the slide back, remove the magazine, allowing the first round to fall through the magazine well, reseat the second round in the magazine and reinsert the magazine. Then releasing the slide will return the gun to service.
Now, remember the comment I made about the extractor groove in those cartridges? And remember what I said about the top round needing to resist the slide momentarily? If the extractor groove front slope is too shallow, there is not enough resistance to the rim of the top round, and the jam will result.
So, my "diagnosis" is not the magazine but the ammunition. And "tuning" the extractor won't make a bit of difference, since the extractor had no part in causing the jam.
What say you, Tuner?