Push Feed
A bolt design where the bolt pushes the round forward and the rim slips under the extractor only once the cartridge is chambered.
In a push feed action the bolt drives the cartridge out of the magazine and forward into the chamber, and the case rim only snaps under the extractor once it is fully seated. The mechanism is simple and inexpensive to make, the bolt-face can be enclosed, and the design feeds reliably from a box magazine, which is why it is common on the precision rifles built on the Remington 700 pattern.
The contrast is controlled-round-feed, which grips the rim the whole way and resists feeding faults at extreme angles. For benchrest and most prone precision shooting, where rounds are chambered deliberately, push feed gives a clean, repeatable lockup that suits the discipline well.