What do Paul Mauser and the African lion have in common?
First lets understand the African lion a little better. Lions eat meat, lots of it. The butcher shop for the lion is an if-you-catch-it-and-hold-it-you-can-eat-it kind of buffet. We've all seen the movies and videos of the lions catching, holding, killing and eating their favorite meal. Wildebeest, Zebra, gemsbok or their favorite cape buffalo. These animals have very tough skin. The buffalo has very thick, tough skin. In order to hold these animals the cats use what is called the dew claw, a claw at the rear of the paw. This is the feline equivalent of our human opposable thumb. The four front claws curl out and back to hold on to the tough hide of the lions' dinner, the dew claw curls out and forward to clamp the animals hide between the front and rear claw like a vice. You can see how this works if you curl your fingers like a cats paw with claws extended and curl the thumb up toward the down curling claws (fingers).
I'll give you all some time to practice this with your mate.
Ok, try to stay focused.
Hopefully my pictures will show this thumb of the Mauser claw extractor.
The extractor on the left is from a model 98 Mauser rifle. The way this thumb (dew claw) works is as the rear tab of the extractor rides in the groove that is cut, a circular slot, half way around the bolt circumference. The extractor has a tab (thumb/dew claw) that has an angled cut which fits an opposite angled cut in this circular groove. It is such that when we pull back on the bolt it pulls the extractor back but it is holding to the cartridge rim with the four front claws (wide extractor lip) and as the extractor hold to the rim it pulls the rear claw under this beveled lip of the cut, holding the cartridge rim tighter and tighter. The extractor cannot slip over the case rim, the bolt pulls the case out.
On some Mauser rifles the dimensions of the groove, and the extractor tab that fits the groove are such that even pinching the extractor at the rear will not allow this extractor to slip over a round in the chamber. The front edge or the extractor can be beveled, the outer front rim of it can be beveled and this groove and angle can be modified to allow thi bolt to close on a chambered round. Some 98's can be closed by pinching the extractor and most hunters want to be able to do this but, we do not want to modify this Mauser claw that fits the angled groove. This is an important part of the Mauser claw extractor and by the way why it is called the claw.
The brand X extractor on the right has no angled cut in the circular slot nor in the rear tab of the extractor. This extractor uses more precise dimensions to prevent the extractor from slipping over the case rim. Note: The groove is more narrow than the Mauser bolt slot.
The second picture is to show the bolts without the extractor installed to better show this groove. Again the narrow groove is not angle cut but more closely matches the width of the rear tab of the extractor. Yes, I can take off a claw extractor. I put them back on too.