Needs review
Source: Player's Handbook

Description: You can fire multiple arrows simultaneously against a nearby target.

Prerequisites: Point Blank Shot, Rapid Shot, DEX 17, Base Attack Bonus +6

Required for: Improved Rapid Shot

As a standard action, you may fire two arrows at a single opponent within 30 feet. Both arrows use the same attack roll (with a -4 penalty) to determine success and deal damage normally (but see Special). For every five points of base attack bonus you have above +6, you may add one additional arrow to this attack, to a maximum of four arrows at a base attack bonus of +16. However, each arrow after the second adds a cumulative -2 penalty on the attack roll (for a total penalty of -6 for three arrows and -8 for four). Damage reduction and other resistances apply separately against each arrow fired.