Jon and Webb,
While I do not by any means have all the definitive info on this subject, I do know that Numrich was offering these do it yourself kits for both the BP and smokeless military actions of the Remington RB for several years, at least as late as the mid-70s. There were two configurations, a "Buffalo Gun" style with full octagon barrel, and a "Creedmoor" variant with half octagon. IIRC, there were both .45-70 and perhaps a few .444 bores available when Numrich was going at the process full blast. At the "peak" of availability, the complete actions were available from the likes of Hunter's Lodge and Navy Arms for as little as $6-7!
The kit contained the barrel, pre-threaded and chambered for the action of your choice along with some fairly pedestrian looking but nicely inletted black walnut and a set of rudimentary sights. As with all things mass produced for the d-i-y market, these kits varied quite a bit in quality and gave a lot of mediocre and some fairly good final results.
My kid brother and I got one of the last sets they had as a close-out sometime in the late eighties, having to "settle" for a Creedmoor barrel, which then turned out to have a slight banana shape.
It built into a fairly nice plinker, and if the barrel HAD been only a little better it would have been a really good little project. That's my story and I'm sticking to it.
Regards,
Froggie
PS Jon, Would you please send me a PM with the current details/progress report on the VA get-together? Thanks! GF