It was once possible to hit enemies who were invisible or stealthed. This made Barrage (already the best PvE talent in the level 90 tier for Warlords) even more desirable in PvP. Because of it, Blizzard changed the ability's behavior in Patch 6.2.0 to no longer target enemies the hunter could not see and added a player penalty to its damage.
Barrage will target and kill critters in addition to regular enemy targets.
Tips and tactics
It's advised to save Barrage for boss encounters due to the ability's 40-yard range habit of pulling extra mobs.
If you do need to use this outside of a boss encounter, carefully position yourself between your current group of mobs and the group ahead (if possible). This will reduce, but not eliminate, the chance of extra pulls.
No longer requires a target, and no longer deals extra damage to one target.
Damage increased by 80% for Beast Mastery only.
Hotfix (2016-09-23):Barrage (non-Survival) damage reduced by 20%.
Hotfix (2016-09-13):Barrage range will now correctly match the range of the Hunter's other abilities.
Developers' Notes: During the recent updates to Barrage, we discovered it extended approximately 2 yards beyond the range of autoshot and other abilities. We're changing it to more closely match.
Hotfix (2016-09-07):Barrage now fires in a tighter cone, and its visual has been improved to better show its area of effect.
Developers' Notes-- Barrage fulfills a fantasy of a wild spray of shots in a large area. Of course, that can be dangerous, and often Hunters accidentally pull additional enemies with Barrage, especially in Legion dungeons. We saw this as a failure on our part to convey what it actually does. This hotfix should allow Hunters to get a feel for the shape and size of it and build a reliable expectation of what will happen when they cast Barrage. No change was made to Barrage's damage. We hope that this helps Hunters and their groupmates to have a more pleasant dungeon experience.
Patch 7.0.3(2016-07-19): No longer available to Survival hunters.
Hotfix (2015-07-13):Barrage should no longer incorrectly hit targets that are in stealth if the Hunter is unable to see them.
Patch 6.2.0(2015-06-23): Now deals only 80% of normal damage against player-controlled targets. Additionally, the ability no longer hits invisible or stealthed targets.
Patch 6.1.0(2015-02-24): Damage has been increased by 21%.