I am not sure of the problem here. Even a badly corroded barrel will often still shoot, and if not, I would think Ruger would replace the barrel for less than the cost of turning the gun into a muzzle loader. But making the gun into a muzzle loader without replacing the barrel wouldn't make the barrel any better.
It is a bit like dealing with a flat tire on my car by making it into a horse-drawn wagon; the problem and the solution don't seem to connect.
FWIW, about any cartridge gun can be made into a muzzle loader by placing an empty primed case in the chamber, then loading the powder charge and bullet from the muzzle. Around 1900 it was common for target shooters to place a case that had primer and powder into the chamber, then load the bullet from the muzzle, a sort of "half" muzzle loader.