Some of the previous answers seem to have it backwards!! The heavier (actually, longer) a bullet gets, the faster it has to be spun to be stable!! 1/14" is the "standard" twist for a .22/250, and will stabilize bullets no longer than the Speer 70-grain semi-spitzer. If you get a 1/12" twist .22/250, it should be OK for longer bullets like the Hornady and Nosler 60-grain and all 55-grainers, whether flat-based or boattail.

Keep yore powder dry!!