Only difference is a slightly larger barrel channel on the "Magnum" stock. Most Remington's have a standard sporter barrel contour, while the magnums have a slightly larger barrel contour with the exception
Of the even larger magnum contour as in the .416's and larger bores. A standard sporter barrel will fit in a magnum stock just fine. The magnum will fit in a standard long action stock but the rear are just ahead of the action where the barrel shank is will need to be slightly opened(Sanded) for a proper free float. I just wrap sand paper around a proper sized wood dowel and work it in the barrel channel until I have the proper free float. It may take a little sanding by hand to get it right.
I often check the fit of the barreled action while doing this, works on wood and synthetic stocks and I always remove the barreled action form the stock on a new factory Rem700 and sand out the two pressure points on the forend of the stock under the barrel. And do any necessary sanding to make sure the barrel is free floated. I double check it by running a dollar bill folded in half length wise wrapped around the barrel. It should be able to slide freely without contact down the length of the barrel to the recoil lug.
