Controlled Round Feed
Also: CRF
A bolt design where the extractor grabs the case rim as the round leaves the magazine and holds it through the entire cycle.
In a controlled round feed action the extractor claw catches the rim of the cartridge the moment it rises out of the magazine, then keeps a firm grip from there into the chamber and back out again. Because the case is never loose during the stroke, the round cannot double-feed or slip free if the rifle is worked upside down or at an odd angle, which is why hunters in dangerous-game country and many precision shooters value the design.
This long-standing claw extractor approach traces to the Mauser pattern and contrasts with push-feed, where the rim only meets the extractor at the end of the stroke. The held grip also gives positive ejection when the bolt is pulled fully to the rear.