bows are rapid shoot (not fire,there is no emission. i know.nerd!) but the more powerful they are the more training they take to use them.
after many years training i can use a 120lb drawweight mongol bow effectivly
english archers were using longbows up to 200lb draw weight but only after years of training.
crossbows can be of extremly heavy draw weight. ive seen and used examples at 5-600lb draw but crossbows used in war take considerable time to load unlike hunting crossbows which can be spanned by hand.
firearms such as those used in the mod which are flintlocks can,like crossbows be used by low tier troops as they take very little training.
like cb's,firearms take time to load. well trained troops can achieve 3 rounds a minute but these weapons are made to be fired en masse i.e volley fire. the better quality marksmans weapons take longer to load as a sloppy wadding will affect accuracy. pistols, especially when used on horseback also take a bit longer to load.
the reason for all this rambling is i think you might be able to use these factors to stop weapons from being overpowered rather than restricting how many arrows\rounds an individual can carry.a bog standard musketeer historically would carry uo to 50 rounds, an archer 50\60 arrows,a crossbowman around 40.
sorry to go on, but ive used all these weapons in the past so i thought i'd weigh in! cheers