I made three cartridges in about an hour. That's two of them in the photo.
I figure three cartridges are plenty. Counting the load in the barrel and three in the cartridges, that's four shots at a squirrel. If that squirrel is still running after four shots from ol' Deadeye Doughty's carbon copy of ol' Deadeye Davy's first rifle, it deserves to live.
The small section of each cartridge is trimmed to hold exactly 10 scale-measured grs of Pyrodex P, the load for my little .32 caliber Traditions Crockett rifle. The large section is reamed so that the small section is a tight, friction fit. For reamers, I used pieces of cane with a tiny bit of sand as an abrasive. When one of the large sections needed extra material removed from its inside, I used the blunt, chisel-like tip of a rattail file handle. A few more minutes with cane and sand would have worked, but, hey, I'm lazy.
I used small cane because I needed small cartridges for my .32 caliber. By using larger cane, cartridges could easily be made for .50 and .54 caliber muzzleloaders. You could even use cane and make powder and shot cartridges for muzzleloading shotguns.
If one of my cartridge sections splits through drying or through use, it won't matter. All that matters is that the friction joint remains tight. If one gets loose, a little dab of epoxy will cure that problem. My great-great-great-great-grandpappy Levi P. Doughty, who came to these Louisiana woods via flatboat down the Mississippi River in 1803, would have simply cut another switchcane and made himself another cartridge.