Re: How can I....
If you don't want to save the barrel..........chuck the action, if it's a Remington, or the barrel if it's something else, in a lathe and use a parting-off tool to make a relief cut just in front of the receiver ring, then with the barrel in a regular vise, stick a small board through the action rails and it should unscrew easily. If it is a Rem, you may have to use a hot air gun to loosen up the mung that is in Remington barrel threads. If it doesn't unscrew easily, you're going to need an action wrench. Anybody with an action wrench should have a barrel vise, though.
If you want to save the old barrel or if you want to install another barrel, I don't know any other way except to find an action wrench and barrel vise.
I hope someone else will jump in that knows a lot more than I do.
Good luck, Tom
Texas State Rifle Association Life Member
NRA Endowment Life Member
A big fast bullet will beat a little fast bullet every time