12mm Unknown

I hope someone can identify this cartridge. The bullet is barely seated in the case and the primer is also not fully seated. If they were, the overall length would be 25mm. The bullet diameter is 11.9mm and the brass case diameter is 11.7mm. There are two slotted pieces of brass forming an X inside the case, which has no powder, just black residue. The primer pocket is hemispherical (round) inside, not with straight walls, with a large, single flash hole. I doubt that the nickel-plated brass primer is original, and maybe not the bullet. The closest thing I found, in Erlmeier-Brandt, is a 12mm Raphael, but this case is 3mm too long for that.

Hi Mel
for some reason I can’t sign on right now but I have your unknown 12 mm listed as the 12mm Pidault & Cordier
Neat to see it apart, the two X pieces supported the, or acted as the anvil. What does the primer cap inside look like?
Doesn’t look to be a primer vent hole in your view of the inside case-base?

Post this if you want

As you can see I got signed in.

It’s hard to see the inside construction of the primer by looking through the primer flash hole, but it looks like the primer has the standard 3-prong anvil inside. That, and it being nickel plated make me think it’s probably modern, not original. But what was original?

The case construction is as shown below, not to scale, in section view. How could a primer with straight walls fit in a primer pocket with a curved shape? The brass X would in no way be an anvil for the primer sticking out the back of the case, and I don’t see how it would be for any other primer. But … that’s why I’m asking for help.

Here is some previous discussion about them The 8mm and 11mm Pidault & Cordier Cartridges (aka Raphael)

From the thread Aaron mentions above here is one of the missing photos from that thread, photo posted by “chassepot”.

Photo description, quoting chassepot-

“12 mm Pidault and Pidault & Cordier long case. The three cartridges on the left are brass tinned, their anvil is in iron”

OK, so what I have is a 12 mm Pidault & Cordier long case with a probable original correct bullet and incorrect modern replacement primer which I’ll probably just pull out and throw away. In the tinned case specimen shown, I can see how the case insert with a different shape than mine has a small teat that protrudes inside the flash hole to act as a primer anvil. But my X insert is different and doesn’t do that.

Thanks, guys. I appreciate the help.