Brownell's sells barrel vises and action wrenches. None of which are cheap. $189.99US for the vise with M14/Garand bushings. They sell generic action wrenches too. $67.12US.
Good pictures on Brownell's site to make either. It's not terribly difficult. Does take access to a machine shop.
Got access to and the skills to use a milling machine? Made a vise and generic action wrench, long ago, just from looking at a picture. Was working in a gun shop and taking night machining classes at a Community College.
Two hunks of steel that are machined flat on the meeting sides with two bolts(used 5/8-11 hex head bolts myself. Far bigger than necessary though) to close it tight and a hole drilled through the middle(side on) to take bushings. Special purpose steel for both and mild steel bushings for the wrench. The bushings were tapered internally to match several milsurp rifle barrels(Lee-Enfield's and M1 Carbine's mostly. Very few semi'd M14's around in those days. Early 80's. Nobody was doing anything to them or M1A's, then. No aftermarket barrels like there is now.). Measured a barrel near the receiver and at about 2" out on the barrel. Figured out the taper and turned 'em on a lathe. Cut in half lengthwise. The cut gave enough distance for tightening in the vise.
Did most of the fabricating on a radial arm mill. Nothing else has enough strength. Mind you, the vise I made was considerably heavier than any commercial barrel vise. Made it out of 2" bar stock, as I recall. The vise and wrench worked just fine changing No. 4 and Carbine barrels. We used a 4 foot, 2", Al bar as a hammer. More over kill, but it worked really well.
Got a milsurp .45 Government Model in trade for the vise and wrench. Had to sell it a few years later to pay a friggin' lawyer.
You'll need a set of headspace guages too. Brownell's again. $27.40US each for Forster guages. You'll need the whole set of three. No Field guage from Clymer through Brownell's.