Vintage barrels have a ¼"-28 threaded forend stud, this info is in the FAQs, there's also a 6mm flathead metric machine screw that's mentioned as working, both are available at Ace and True Value hardware stores, I bought one for my M158 barrel, get a 1" or ¾" and cut it to fit if too long, buy a nut at the same time, run it on the screw first, then cut it with a hacksaw, chamfer the edges of the cut end with a file, then run the nut off to clean up the threads, it'll work perfect, done it thousands of times since my grandad taught me the trick about 50yrs ago.
Brownell's is backordered on the spacer, Numrich and H&R have them, screws are #6 flathead wood screws.
Tim
http://www.gunpartscorp.com/Products/279370G.htm
