Bach could have owned a matchlock or wheellock weapon or two.
Germans are famous for developing target shooting during that period, and modern Shuetzen competitions can all trace their roots to that period.
Contrary to popular belief, rifling the bore was already developed by the beginning of the 1500s. However, the towns' magistrates decided that target shooting with these rifled guns were blasphemous, because they believed an imp was present in the rifled guns that made the balls fly with greater accuracy. Thus, the highly superstitious people at that time became frightened, and thus, rifling remained dormant until the late 1600s, when American Colonists began using rifled flintlocks in the backwoods.