I'm curious where you get this information. The bevel doesn't change the extractors ability to do its job extracting in any way I can tell. If it will cause the extractor to break, I doubt Springfield would have done the 1903's that way, or Ruger, or any of the other makers, including all the commercial Mausers made that I've seen. The extractor on all of those are functionally identical to the military Mausers, only they have a bevel on the front edge to allow the extractor to snap over a cartridge rim. So far I haven't heard of any rash of broken extractors in any of those guns.
Wrong. It is tight because it is not meant to be loaded like that.
What does this mean? The OP said he noticed it being "tight' when he chambered a round with the magazine in, and it wasnt tight when it wasn't loaded from the magazine. It sounds like it's less tight if he simply drops a round in rather than feeding it from the magazine, the opposite of what you have said is the only right way.