You can get a barrel vice and wrench from Sinclair and other Reloading people. I have one. They are not all that expensive, but the action wrench is pretty specific to each manufacturer. I have one for my Neseka action custom that goes through the ejection port in teh action. I've seenone for Remington that uses the back end of the action where the bolt is removed. It takes about 30 seconds to drop the installed barrel and thread on the one that is not installed.
I will post a pic or two tonight of taking off a mauser barrel, along with the needed tools. Some actions may require light heating to get some of the super tight barrels loose. Use caution though with heating, and try a cheater bar first.
I've never not been able to get a barrel off by just using a cheater bar. The first one I ever took off I just bolted the old mauser action to a shelf using some "U" bolts, then a pipe wrench with a cheater bar to twist the barrel.
If you plan to do more than one, get an action wrench. If you are just doing one, clamp the action down and use a pipe wrench on the barrel (with cheater bar). Just be careful on how you clamp the action down, you do not want to twist or otherwise tweak that action (it would take a lot of force)
heres one way-
If the barrel doesn't mean **** just put the action in a clamp(protected by rubber or thick leather), drill a good sized whole through the barrel near the base, then slide a long bar through and unscrew it. If you try to unscrew it by twisting the action its likely to get bent or mangled somehow. If it is like a Rem. 700 action take care, since they are round they are difficult to secure. good luck
I helped a friend of mine who is a gun smith take bbl of an old mauser. He supplied the brains and we both supplied the muscle and cheater pipe. It can be done but I would have someone show you how first. He gave me a couple of tips while we were doing it. Kroil oil soaking into the threads for a while BEFORE you take it off. Most just screw into the action, but you do not want to bend the action. Also putting a bbl on is not hard, doing it right is a little more complicated.