All pre-64 Winchester Model 70's and Model 54's will work very well when single loaded and the extractor easily snaps over the rim. All of the post-64 classic rifles from New Haven, which are chambered for a standard cartridge will also work well. Those which use the Williams extractor will often not work that well when single loaded because there is not enough clearance between the tang of the extractor and the bolt body. This is pretty difficult to correct when the problem exists.
Many people have bought into the "it's a CRF action and has to be fed from the magazine" BS. It seems even Winchester has bought into and use it as a n excuse for making a rifle which doesn't work as it should. Williams has bought into it as an excuse to make an extractor which doesn't work as it should.
By the way, if you try to single load a Mauser, all you have to do is press on the tang of the extractor while closing the bolt and the extractor will snap over the rim and allow the round to be fired and extracted.
My comments regarding the oval WSM chambers were made because the OP stated that he could not chamber some rounds unless he rotated them at which point they would chamber. My mistake for not reading the later post. I can theorize as to the reason these cartridges would feed singly if re-indexed but there is little point in doing so. GD