Hi Folks and thanks for looking,
Let me answer some questions raised. The breech is a simple powder chamber, not a Nock breech. Here are some photos:
The powder chamber is about 0.375" in diameter and the bottom is radiused and polished. The White Lightning vent liner is positioned at the very rear of the chamber. The mouth of the chamber is funneled. The idea is to provide the efficient powder ignition of a chambered breech, which increases the force of a given charge, but also make it easy to clean. The 4140 steel is very tough so the breech should be very strong. I do not believe, with modern powder, there is any significant advantage to a true Nock breech. I have not shot the gun yet so I will see if my decision is a good one. Most English guns of that period had some form of chambered breech (not always Nock's design) so, perhaps, I will learn why when I shoot the gun.
The barrel is browned in contrast to the breech. An original English rifle from this period would have a stub twist barrel. Those barrels would be browned. the breech color case hardened or charcoal blued. I learned a lot here, mostly from some old British technical journals. I wanted the reddish brown found on those great stub twist barrels.
I learned the color was not feasible for modern steel barrels. With twist barrels, the old makers used just 4 or 5 cycles of browning, which left a very red finish but uneven. That was not a problem because of the marbled effect of the stub twist. The uneven brown look like a feature not a bug. On a modern steel barrels, that uneven reddish brown looks like an uneven browning. When you do more coats of browning to even the color, you inevitably get a darker, more plum brown. I learned how to keep most of the red color during browning but it was a learning process.
JerryH, the finish is actually not that glossy. The low angle light and snow still prevalent here in Vermont accentuates the glare in ambient light. In neutral light, it looks very much like the semi-gloss finish on original British guns from the period.
dave