Re: Remington 700 SA
the feeding has to do with the feed rails, not the length of the magazine box. Any problems that would manifest in a short action will also manifest in an action made for a standard caliber long action such as a .30-06/.270 and the like.
Building the 7WSM will give the ability to seat bullets out further while feeding from magazine legth, which does have some benefits, but the caliber was designed to be utilized in a short action.
Hope that helps a little.
Dave