Thanks for the clarification on models and shipping dates kuduae - without this sort of input, one does not learn.

The only 8.15X46R's I've seen (probably only around 1/2 dozen of them in total, were the single shot target rifles (Aydt, I think they were called).

My model 71 - marked on the right side, 1876 1876 is marked on the left side, as you said - Mod. 71 (or what looks like Mod. 71)

I do know it differs from the model 71's marked 1884, in that the 1884's appear to have .446" groove diameters, whereas the 1876 I have, has a .458" groove diameter, even though chambered for the same round with a .446" bullet - thus my choice in rechambering the rifle to a .45 calibre round.

Initially it had a .437" bore and .457" groove diameter. After re-chambering and firing 40 firelapping loads it now measures .438" X .458".