The claw!
All of these rifles were designed to feed from the magazine. About 50% of the Mauser 98 rifles are magazine feed only, that was to prevent double feeds. I think it resulted in enough broken extractors, that the extractor claw was rounded, such as in the Dumoulin Mauser, to allow the user to drop a round in the chamber.
A bud picked this up at the range, and we puzzled over what could cause this
Then the light bulb went off, and we decided this was a magazine only Mauser extractor that someone absolutely beat to hell trying to close the bolt on a round placed in the chamber. The claw is missing. We also think once the user found the claw broken off, ripped the extractor body off his bolt, and tossed it on the ground in disgust.
I am going to say, regardless of whether you have a controlled round feed action, or a push feed action, always feed from the magazine. If you have a controlled round feed claw extractor rifle, it is only a matter of time till the extractor breaks from having to snap over a cartridge rim.
Sometimes the owner is over a barrel. I have a very early Ruger tang safety M77. Ruger made a faux controlled round feed extractor. It looks like a Mauser, but it is not. It is, in fact, a push feed extractor.
This extractor has to stretch each and every time it snaps over a cartridge rim. And in time, they will all break. And I think Ruger stopped making these decades ago.
This is a later M77 extractor
While it is 100% better to only feed from the magazine with this Ruger M77 extractor, you can place a round in the chamber and close the bolt. But do that enough times, and the extractor will break.
This is an example of an early push feed extractor. The extractor has to snap over the cartridge rim.
A push feed extractor will wear out in time, some break, it is just the nature of the beast. Because they are designed to flex, they will generally last a long time. This is an AR15 push feed extractor. The extractor has to snap over the rim.
But Stoner designed it to pivot. That pin in the middle is a fulcrum, the extractor is spring loaded at the end. This extractor will teeter totter as it snaps over a cartridge rim, so what wears on one of these, is the claw. The claw eventually will wear due to mechanical abrasion and then cartridges won't extract.
That M1917, it is best fed from the magazine. I had a round jump in front of a M1903 bolt face, during rapid fire. While the M1903 was designed to allow a cartridge to be placed in the chamber, and the bolt closed, the claw broke. Bummer.