[HoneyBadger]

It was a Wikipedia reference (I like it because it's easy for everyone online to follow, much more easily referenced than a lot of out of print texts, and while it may not be perfectly accurate, it's accurate enough for a game), but I'd like to point out that I actually own a crossbow, that I'm very familiar with their use, and traditional construction-including the steel versions-
that I've spent over 3 decades studying the history of arms and armour, and that I grew up around such. My father professionally appraised swords for auction-houses, for years, and my family has an extensive collection of books on the subject, and on medieval weaponry, in general.

You're welcome to argue the point, but 2 accurate shots a minute is quite doable, even with a heavy crossbow, using a common windlass, provided you have enough upper body strength, and training.
30 seconds may not seem like much, but it becomes quite a lot of time, when someone's threatening your family with an axe.