The body of the action is the same. In fact, the only real difference in the actions is the bolt face counterbore on the Magnum Chamberings is larger in diameter.
Even the action body for the big super boomer Ultra Mags is the same.
The accepted method with the HS Stocks, (the ones with the full length bedding block), is to 'skim bed" the action. The reason?? Not all actions, and bedding blocks, are a good match.
Rough up the aluminum bedding with some course sandpaper. Make sure it is clean, with a capitol "C".
Smear a thin coat of JB Weld or Devcon on the blocks surface. Put a release agent of your choice on the action, (I use nuetral Kiwi Show Wax), and on the action screws. Place the action in the block and install the screws just barley snug. Very lightly tighten the rear screw just untill the tang seats. Take a look to be sure everything is straight, and let the Devcon set.
After it sets for at least 8 hours, pop the action out. You should have a perfect bed. Clean the action of any bedding that might have stuck, and sand away any spill over. You should now have a perfect bedding job, ready to tighten your new action in........jackie