Board Thread:General Discussion/@comment-16399478-20130614235641/@comment-10870829-20130615010746

Oh and one thing I should mention, CROSSBOWS ARE AWESOME! way better than bows. Most of my Dark Brotherhood kills were done with a crossbow snipe shot.

As far as I know you can get a crossbow as a vampire (by taking it off a dead dawnguard) but you can only buy crossbow bolts, or learn to smith them after siding with the Dawnguard. You can loot Dwarven crosbow bolts from dwarven spheres but they only drop 10 each which means you would have to spend a lot of time looting dwarven ruins.