So the first thing I did was to try and put a 2.5" cartridge in the chamber... no go.
I did a chamber cast and was very surprised to see it was a very short chamber. Remembering Lancaster's pictures on another post, I saw that in Germany a 40mm length cartridge was used. I believe that is what I have.
The major of the bore is .615 and the minor is .600.
The cast bullets from the mould came in at .615 +/-, 340 grains.
Inside the case, not original but very old it says "2 1/2 drams of Curtis and Harvey with 3/4 oz ball or 1 oz. bullet"
I would be interested to hear what the smokeless equivalent could be. I plan to shoot it this week.
JZ