Unless you want to register it with the ATF as an NFA SBR (short barreled rifle) you cannot turn a rifle into a pistol (Barrel shorter than 16")

What you can do is buy a new action that was never made into a rifle, making sure that nobody logs it in our out as a rifle anywhere between Savage and your FFL dealer. Have them log it out as a pistol then you are good to go.

You can turn a pistol into a rifle later if you want and back to a handgun etc. as long as the barrel length and shoulder stock regs are followed and nobody logs it in our out as a rifle, but the same is not true of a rifle action. Once a rifle, always a rifle.