Ah, for the powder charge, just fill the case w/ black powder and set a bullet atop it. That seems to be the correct manner in which it was loaded. You could fill the case & see what it measures. But I would fill the case & check the velocity. I suspect it was around 1500 ft/s. But where the bullets land up on the target @ a distance of 100 paces just may be the test?

Cheers,

Raimey
rse