Savage wanted a bit more metal around the short fat magnum cartridges, so they developed the large shank action. For a variety of factory barrels check here:
http://savageshooters.com/SavageForum/index.php/topic,38060.0.html
All that is necessary to do the swap within the same action length and case head size is a barrel, barrel nut wrench, vise, and a go gage. If you need to change head size, you would need a new bolt head and possibly a mag box.
