"Bolts should weigh a hundred pounds and be well-balanced. You will know your bowstring has perfect tension when you hear the Nimbian winds resonate it at F-sharp above Middle C." from The Sixth Archer's Handbook

The Crossbow is a self-aiming Shooter.

As you're preparing to build it, right-click to aim it in one of four directions. The Crossbow will target the closest unit in an arc. Crucial to fending off attacks by air, the Crossbow packs a precise wallop.