I have a newer 700P that you can single round feed by just laying a round on the follower and running the bolt closed.
I have an older 700BDL that absolutely will NOT feed a single round unless it is pushed down into the magazine. If you do that, the rifle works fine.
The 700P is a .308 and the 700BDL is a 22-250.
I do not know if cartridge shape or size is what causes this difference, but it is there and has been there since day one.