The OP's question was specifically about a shouldered barrel on a Savage. He got his answers.

Leonardo stated he'd put a nut on a Mauser. I pointed out that a Mauser doesn't headspace the way a Savage or for that matter any other rifle does.
Herr Mauser's design requires machine work to set the headspace and a shoulder or a nut is unnecessary on that particular design.
A good gunsmith will cut a shoulder on a Mauser about .002" more after the breech contacts the C-ring (H-ring in some later or cheaper Mausers/clones) and fitting the barrel results in a crush of that .002" so that the shoulder contacts the receiver face. The breechface/C-ring interface is what establishes headspace though.