Although factory barrels can be installed to unnecessarily high torque, and/or with some kind of thread locking compound, once they have been removed, on in the case of a custom rebarrel, all that is needed to remove and replace a barrel is a barrel vise of the low torque variety, like benchrest competitors use (that do not require barrel contour specific inserts) and and the proper action wrench for the specific action being used. Savage's barrel nut system is only an advantage because it allows users to buy pre-threaded and chambered barrels, that can be installed without the use of a lathe, by setting the headspace using the nut, and a suitable gauge. Barrels that are fitted to a specific action by a gunsmith, are easier and more convenient to switch because the headspace setting is built in, by virtue of the position of the barrel shoulder face to the headspace gauge, when the chambering and fitting was done.
And here's how to make a prefit work like a shouldered barrel... Get the barrel set for headspace and drill and tap for an allen screw ( I go 50 thousand's in to the barrel its self) Now it works just like a "shouldered barrel" but you could remove the allen screw to set it up for another action. I have 3 6br's , a 30br, a 6dasher and 3 6.5x284's set up this way.