Sorry, I misread the above post thinking he meant WBTS cartridges.
Honestly, I am not sure which end went in first. The times I've made and used paper cartridges with balls in my Brown Bess, I always loaded the torn paper end first and never had a misfire.
However, I can see by the way the English made their cartridges for the Enfield Rifle Muskets with the base loaded first and the excess paper torn off, this may have been an extension of loading the bullet first in the 18th century.
Gus