This may be a dumb question but I was wondering what the difference is between the Rem 700 actions and the Remington 700 SPS actions? I am planning the build of a gopher getter and high speed paper punch, out to about 600 yards. I am leaning toward th3 6mm br on a short action, or a 6mm rem ai on a long action. Are the SPS actions a good candidate to build off of?