@Haeo You could use a specially designed crossbow that did the same thing~
Indeed, this is so. Though, the custom engineering involved in either structure would require a higher level of education than most of the character backstories include. Not that many people would know the principles involved in making a crossbow back then. It was professional knowledge, never mind customizing one for throwing sacks of liquid or other irregular projectiles.
Though, it can be difficult to avoid large stacks of clichés if one clings to the existing concept of what is nature related too tightly.