Wikia

Volley
Volley 35 yd range None cooldown 17% of base mana Instant cast Requires Ranged Weapon Continuously fires a volley of ammo at the target area, causing X Arcane damage to enemy targets within 8 yards every second for 6 sec.
Usable by
Class	Hunter
Properties
Type	Offensive
School	Arcane
Cooldown	None
Talents
Level required	40
Improvement talents	Hawk Eye, Efficiency, Barrage, Improved Barrage
Other information
Ranks	6
Requirements	Requires Ranged Weapon

Rank table

Rank	Level	Mana Cost	Damage	Training Cost
1	40	24%	[RAP * 0.0837 + 52]	1 80
2	50	24%	[RAP * 0.0837 + 79]	3 60
3	58	24%	[RAP * 0.0837 + 105]	4 80
4	67	17%	[RAP * 0.0837 + 168]	14
5	74	17%	[RAP * 0.0837 + 290]	30
6	80	17%	[RAP * 0.0837 + 353]	30

Prior to Cataclysm this was the only true ranged area damage the Hunter can do. Since Cataclysm pre-patch Multi-Shot takes the role of ranged area damage.

This is a channeled ability, so any damage taken will cancel the effect. (As of patch 2.0 this can be overcome with rank 3 Improved Barrage talent.) Also mobs may leave the area of effect.

/ Patch 4.0.1 (12-Oct-2010): Removed.
Patch 3.2.2 (2009-09-22): The attack power coefficient was raised from 5.86% to 8.37% (undocumented change)
Patch 3.0.8 (2009-01-20): The damage has been reduced on all ranks by approximately 30% (including attack power scaling).
Patch 1.5.0 (2005-06-07): Damage increased.