Generally a semi-auto is designed to feed from the magazine ONLY. The general design is as the slide moves forward it hits the back of the top round and spring pressure slides the bullet up under the extractor at the same time it is pushed up by the magazine. Some guns have a spring loaded extractor and are less prone to being damaged by loading the chamber directly, but in the long run it will wear the sharp edge off the extractor prematurely even with the spring. With no spring you are forcing the extractor to flex or bend around the case rim. That can cause chipping/cracking of the extractor,loss of proper pressure on the extractor as it is flexed back and forth and problems with the cases if the case is reloaded.

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