I know that it's counter intuitive, but I am convinced that straight sided cases extract better than tapered ones, particularly in single shot actions with little or no primary extraction. I think the reason is simply that single shot actions, as opposed to bolt actions, have a certain amount of "give" in them, and when a tapered cartridge is fired, the action springs slightly, which allows the cartridge case to obturate to slightly more than the normal chamber size. Then, when the pressure subsides, the action snaps back, and the now oversize cartridge case is driven forward into the chamber, where it is tightly wedged and resists extraction. A straight sided case would not have the same wedging action and therefore extracts easily.

Incidentally, I have a .25-.222R on a Winchester Low Wall action and it extracts flawlessly. Of course, the lack of strength of the Low Wall limits me to rather mild loads.