You can load crossbows with blinding speed and even fire them in melee with little fear of reprisal.
Prerequisites
Dexterity 15, Rapid Reload, Rapid Shot.
Benefit
The time required for you to reload any type of crossbow is reduced to a free action, regardless of the type of crossbow used. You can fire a crossbow as many times in a full attack action as you could attack if you were using a bow. Reloading a crossbow no longer provokes attacks of opportunity.