This is how I make realistic looking blank Civil War riflemusket cartridges, for the Reenactors who are truly serious about high standards of authenticity. These rounds are replicas of the common .58cal riflemusket cartridge, made to the specifications of the 1861 United States Ordnance Manual. Confederate cartridges varied widely, and while they never made specifically the 1861 US version, these cartridges are extremely close to the versions produced by Southern arsenals.
I recommend Fourth Armory’s templates and mandrels, you can find them here;
https://www.fortharmoury.com