You should not have any magazine problems with your swap. Your rilfe should be small shank, so any small shank will fit. In a 308 heave barrel I would not use a break, just a decent recoil pad. If you use a break you MUST wear hearing protection while hunting. You will need to open up the barrel channel of your stock to get the barrel to fit or buy a used or aftermarket stock(factory take off $40 or so, Boyds blem stock about $60 but pretty heavy). I think SSS is about $300 for the barrel, 125 for fluting and about 150 for a brake. If you email me I will sen you a pic and price when I get the barrel. firstname.lastname@example.org
Take-off Barrels can be had from private parties mostly.
New barrels from Sharp shooters supply, douglas, pacnor, lothar walther, as well as many more if ordered. They usually start at about 300. Most heavy barrel rifles are about 650+ I usually check prices with www.budsgunshop.com
to get ideas about cost.