The XM action is a extended medium action which is good for cartridge length up 3.2 inches. This action was designed for the longer short action calibers like WSM's or 6.5-284. Defiance medium action is the same as a Remington short action not sure why they named them like this. For your application you would want to go with a long action.
Last edited by sorth; 10/21/12.
