Action wise not one thing. But with that said let me explain a little further- the 40X is supposed to be trued up by the custom shop and a little tighter tolerances. However I have worked on several and they were as far out of true as a normal 700. One other difference is they make the 40X in a single shot version as well as a repeater. The 40X also has a slightly different and better trigger. The # screw/spring is a little better design allowing for a more consistent pull weight.
However, 700 can be made to shoot as well as a 40X and the 700 trigger can be tuned to be just as good.
So in my opinion, buy a 700 and spend the extra $ on a good barrel or glass.
