As I remember, the Remington 700 is a push-feed system. That means the round must pop-up completely loose from the rails (where as a controlled feed system the extractor "captures" the round before it is released by the rails), in order for the bolt face to push it into the chamber. Try watching as you slowly push the bolt forward...at some point, the round should pop-free of the rails. If it does not, the bolt will ride over the round and jam. Note: a rail problem is more likely with a new gun. If this is an old gun that just started having this problem there are other considerations. Are you shooting hand loads or factory? If neck-sized hand loads, the bodies of the cases are slightly larger in diameter than factory, and could be causing some binding in the magazine.