Action length is generally determined by the cartridge. 300winmag and 300RUM definitely need a long-action. Whereas the 300wsm, although designed for short-actions, can be built on a long-action if you want. (I am unaware of a factory rifle in 300wsm on a long-action)awesome. thanks for the advice. is there any advantage or disadvantage to the size of actions other than the pro and cons of the certain bullets each can use?