I don't think that the action make plays that big of a role in the accuracy department as compaired to the barrel , the job done putting the rig together and the loads.
Rem 700 are so popular because their easy to build on and they have a pile of aftermarket parts , I don't believe that a Remington 700 is any more accurate than a properly put together Win70 , Sako75 , Browning A-bolt or Savage for that matter.
I've seen old Mauser 98's that would shoot under a 1/2" with a bunch of loads , it was barreled with a CM standard Pac-Nor barrel and chambered for 308Win , no special neck or anything else just standard 308Win
I think the fact that Darrell Holland put it together for one of his friends played the biggest role.