The Crossbow Expert feat lets you use a Hand Crossbow in your offhand and take a shot when you attack with your main hand.
Most people I've seen, seem to think this will allow Dual Wielding Hand Crossbows. What I'm curious about is if you get dex mod to damage on the second shot. There are two lines of thought I've come up with on this.
Either it follows the TWF model, where you do not get the offhand weapon's modifier without an extra feat, or it follows the Monk's Bonus attack model, which grants the modifier.
I'm not sure which way to land on this.
For instance: Per round, with a +4 Dex, Crossbow expert deals 67% more damage vs AC 15 and 112% more damage vs AC 17. You simply have more, better chances to hit.
Avg dmg: Longbow vs 10 AC 9.47 Crossbow vs 10 AC 11.60
Longbow vs 15 AC 4.85 Crossbow vs 15 AC 7.85
Longbow vs 17 AC 3.00 Crossbow vs 17 AC 6.35
Longbow vs 20 AC 1.15 Crossbow vs 20 AC 4.10
http://anydice.com/program/e209
– andrew Jan 03 '18 at 17:08