Re: Short or long action???
More accurate? Who knows. What is known is that a shorter action is more rigid than a long action, its lighter than a long action and easier to carry a shorter rifle than a long one. If you are not wanting to reach RUM velocities or such, than the short action mags get my vote. Yes you can get about the same velocity with the short mags as the standard mags. Less powder, same velocity, less recoil, better bbl life and an inherently more accurate case design, you would be foolish to go with yesterdays mags unless you want/need MORE POWER! Then go long and go all out, otherwise a long action makes little sense.
Long range shooting is a process that ends with a result. Once you start to focus on the result (how bad your last shot was, how big the group is going to be, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.