It's definitely possible. The Merkel double rifles are built on their same 12 gauge frame with no differences. That same action is used by Rigby to make their big doubles. You will have no issues at all with the strength of the action. The concern is making sure the barrels are fitted flawlessly to that action. If the barrels are not fitted to perfection, no action made will withstand the punishment of the recoil for very long.