Thanks Pete and Dave
Bullet weight is 177 grains, 1.425" long. Solid turned copper or GM.
The “unfinished” case does not belong to me. The owner told be it was unfinished. That’s why I used that description. It’s obvious that the pocket would never accommodate the electric primer of the loaded cartridge. It appears to be a conventional primer pocket but I’m only guessing, based on the photo.
My loaded round has a primer pocket that is approx .310" - .315" diameter. I can’t measure it any closer than that without punching out the primer. The “flashhole” appears to be a raised projection inside the case base, about .115" in diameter, sealed with some sort of dark color material. I assume this is typical of the French primer?
FWIW, powder is a very fine spherical, 43.7 grains. OAL is 3.120".
So Dave, I take it that there was no rifle as such. Only a test barrel and receiver?