When it comes to badass knight weaponry, the Medieval Crossbow from ARMORS is about as close as it gets to owning the real deal. ARMORS is a shop on Etsy that sells multiple styles of crossbows as well as shoulder armor and bolts to go along with the projectile slinging weapons.
The Medieval CROSSBOW has a tension of 14-16 kg and comes with a steel arch that it demountable. For the grown man who always dreamed of living in the life of a knight, the Medieval CROSSBOW from ARMORS will definitely give him a small dose of the dragon-slaying lifestyle.
There's probably some rules and regulations that would come with owning a Medieval CROSSBOW. Like any weapon, you'd probably want to keep this away from kids.