Three to four hours from billet to monoblock is pretty good time there.
When it comes to machining parts, once you know where you need go go from barstock to product getting the second, third, fourth... part done is quicker each time -- even if they're simply similar but unique parts. Speeds, feeds, cutter geometry, tooling setup, cutter path -- it all comes together a little better each time.

If the aptitude is there, a man can go from operator to produciton machinist pretty quickly if the tools and coaching is there to facilitate the development of a steep learning curve.

The Stevens idea came more than anything from the charming looks of the cartridge. I'll be going smokeless with that one for sure, extraction will be much less of an issue with clean-burning modern powders. I have a little pile here of sixty pieces of Bertram virgin brass in that caliber, I won't likely need to turn any brass for the thing in this coming decade.

The eight bore C&H on the other hand almost certianly will be a blackpowder chugging roundball machine.
I'll have the barrels made of good modern barrel steel so I'll also be able to cook up smokeless loads for it without worry, but I want that thing to be a charcoal burner.

Really, I'd also like to find somewhere a pair of damascus eight bore barrels for it and saddle them on a set of shoe lumps juuuust to have an eight bore damascus side by side shotgun with a pair of rifle tubes to go with it. I know 8b shotgun totally impractical, but I just don't care. I'll most likely go with a smaller guage than eight for the rifle tubes too, likely twelve or fourteen.

I'm constantly (although waaaay in the back of the agenda) peeking around for a pair of damascus eight bore tubes offa' *any* side by side shotgun.
If you find a pair of them let me know.

--Tinker