I have a 1917 U.S. Enfield rebarreled to .458 Lott; it had already been visited by Bubba when I bought it, so I wasn't butchering a collectible milsurp. That said, you would be time and money ahead to simply buy a commercial rifle chambered for the cartridge that you desire. Fifty to sixty years ago, any gunsmith worthy of the name was familiar with the work that goes into 'sporterizing' one of these rifles. That is no longer true, and parts are also no longer readily available.
Top Gun .357 Sig Club Member #55
Official M1911 Club Member #21