Heavy Crossbow of Speed

Keep On The Borderlands

This magical weapon of Dwarven manufacture is +1 to-hit and damage, though it may only score hits on creatures requiring magical weapons if it is armed with a magical bolt.

The crossbow automatically cocks itself, so that it may fire once per round. It does 2d6 damage. It is a very large weapon, requiring a mount or a second person to hold and balance it for the firer.