Your idea of a double rifle .41 Magnum is an interesting one, but probably not very practical.
The action itself is probably strong enough, IF it is a recent production (within the last generation of so) model. The earlier ones were made of semi-steel or wrought iron. The 310 action came in various breech face wall thicknesses. I'd advise investigating this before proceeding. I once examined a sleved double barrel shotgun action converted to .223 Remington. It was only fired a few times and ended up with .223 casehead sized holes punched into the breechface.
The .410 shotgun bore and chamber dimensions are not suitable for the .41 Magnum. At the very least, the barrels will need to be cut to stubs, the stubs bored out, and re-fitted with proper .41 Magnum rifled barrels, and re-chambered. I know of no re-rifling speciaist that will tackle a re-bore of your double barrels. As you probably know, re-rifling involves boring and reaming on a lathe and then running rifling groove cutters through the fresh bore. Setting up to do double barrels would be spectaularly complicated AND expensive. In addition to the barrel work, the firing pins probably need to be re-fitted and the firing pin holes re-bushed for the much higher pressure .41 Magnum.
Why the desire for a .41 magnum double rifle? There are other calibers that are easier to convert to and provides equal or superior ballistics.
