years back I needed a bore guide pretty quick being as I somehow manage to loose one. The chamber was a custom wildcat with a .262 neck. So I get the grand idea of just making one out of some Delrin stock I had laying around. WRONG! After about six tries I'm moving into a panic mode, and needed the guide really bad. I have about four or five once fire cases laying around, and got a plan (now don't laugh too hard). I stick the case in a lathe, and drill a hole (.31") thru the primer pocket. Take the case an clean it out and degrease it completely. I then take a piece of 5/16" hydraulic tubing that's about ten inches long, and deburr both ends and clean it. I mix up a batch of Hardemans two part epoxy, and with a swab coat the I.D. of the case as best I can. Then out on one wnd of the tube I do the same on the O.D.. Slide the case over the tube, and kinda align it strait as best I can. Then I stick it in the lathe and then hold the fired case strait in a drill chuck in the tail stock. Twenty minutes later it's done (well almost). I now take a reamer that's just a few thousandths bigger the the I.D. of the tube and clean it out. After all that's done I made a collar to hold it in place. Worked very well except when using something like Sweets 7.62. Then I come up with another grand scheme and literally coat the O.D. & I.D. with a thined epoxy solution. (needs to be about as thin as milk). Clean up the case end a tad and it actually fit the chamber even better. Been using it now for about seven or eight years. I've since made a few others like it. They're not perfect, but the first one was far better than waiting six weeks and paying out the nose for one.
gary