Hogeye: Taper on a case does indeed make feeding and extraction easier on conventional actions. However, in the Contender a tapered case is a detriment because it increases case head thrust. That is why you can shoot a .223 in a Contender at 55,000 psi but cases with a .473 head diameter should be limited to 46,000 psi to avoid stretching the frame. A straighter wall case grips the chamber a little more strongly at firing than a tapered case and reduces the force on the weak (compared to bolt action)lockup of the under lug Contender action.
