How easily can the barrels be changed on these rifles?

Loosening the original factory barrel takes a little effort. After that, it's child's play.

With no mechanical skill at all, it takes me less than five minutes to switch from 223 Rem to 30/06 or to 416 Taylor.

Might want to check out www.savageshooters.com

Hammer

A set of go/nogo gauges should be taped to each barrel when you take it off so they can be found easily when you're resetting the headspace during the next instalation. Cheap insurance since a blown case will at best scare you, and at worst, lock up your acton or take off the side of your face!

Safe Hunting
Clint