I'm running a campaign where the Renaissance era firearms on page 267-268 of the DMG exist. I notice that the rules for gunpowder are under "explosives" and not firearms, but still includes the quote, "gunpowder is chiefly used to propel a bullet out of the barrel of a pistol or rifle."
Do my players need to keep track of both bullets as well as gunpowder, or do they just need to keep track of the bullets? Also, how many shots would a horn of gunpowder be good for, as made available in the DMG on page 268. The second question only applies if they need to be keeping track of gunpowder.