Those Cowboy 45 special short brass cartridges are akin to the cartridge that was chosen for the 1860 Army when converted.
Makes sense to me to use something akin to what was originally used to convert the Army revolver.
I forgot what powder charge was originally in the 44 Colt cartridge but it wasn't a magnum but still served well. Was it 22-24gr. powder?
I thunk......really......using a bullet with a short bearing surface and close to the weight of the ball would have an Army workin well fer a long time.
Having an alignment of the chambers to the centerline of the bore that was proper would be a good thing for longevity as would using a bullet that was sized to be right at what the barrels groove diameter is.
Using pure lead bullets and not hard cast bullets would help longevity also.
Of course using the ball in the cartridges would be easier on the gun then the percussions loads since the cartridges hold less powder.
Only thing to contend with using the ball would be finding a way to lube the danged things.
An Hombre or Hombrete could always go to a lil exra trouble using the balls and make wool wads saturated with a wax/lube or go all the way and make some lube pills(grease cookies).
I've loaded the balls in my brass. Works good. Not real hard on the Army revolver. Full loads of powder in the 45 Colt cases is a lil hot but the loads of powder in the 44 Colt is alright fer the 1860 Army.
Using balls in the 44 Colt cases is actually easier on the 1860 then the percussion loads.
Optimum ball size is .430 but that requires a modified ball mould or....the .433's from Speer can work...depending how the seat-crimp die you use is. You can always make a steel swag with a .430 hole and a slight funnel to the beginning and size the balls from .433 to .429-.430. That makes a slight band around the ball to orient it in a case.
Anywhoooooo.......I still have an 1860 type revlver chambered in 44 Colt and that's what I use since 44 Special is too long i that gun. It's fired thousands of smokeless and black powder cartridges and is still like it was in the beginning. I stay with the 200gr. bullet and keep the velosities close to what the black powder load gives.
That danged 44 Colt chambered 1860 seems to hit everything it's pointed at even if it's loaded with the lead balls. The black powder loads can dirty the shallow rifling and cause some strays but if the lube pills are working it stays on course.
The softer the lube is the better it works but....it's hard to handle very soft lube pills to load the cartridges.
I harden thema bit with an extra bit of paraffin and if need be swipe a jag and patch thru the chambers and bore now and then.
Now and then when I'd out shootin and the hound gets loose I thunk he tracks me by scentin the dirty patches. Maybe....he scents the black powder smoke on the breeze.