I would look into the savage target action, you can get it designated as a pistol. There are plenty of options for stocks, Joel Russo, Neal Cooper and mcree precision. And you can use the savage barrel nut system and change barrels yourself... I love mine!
As pointed out above, illegalities abound with 700actions in pistol applications. XP100 pistol actions are essentially the same as model 600 rem. and model 7 rem., MOA Corp. makes a strong "falling block" pistol in a large variety of calibers,see the website
After posting this i have found several savage build on the target action that seems to interest me. I'll probably head that direction. Are the savage target action the same dimensions are a regular savage 10 other than they are single shots?
I'm not sure about the screw spacing, but they look to be very similar. The target actions are all large shank also, which means magnum calibers are ok.
My action came from northland shooters supply and when my ffl recieved it I had to have him check pistol on the initial paper work.
So would it be better to use a target action or a varmint action for a 300wsm? the reason i ask about the spacing is the whole 4.25 to 4.4 or whatever it is....