Guided arrow being able to pierce is a thing of the past. Back in .09 you shot one off and it just kept hitting and turning around to attack the same target, but that was killed when this patch came out.
For reference, bad idea to post the same thing in more than one place. It's considered spam and is a bannable offense. It's not good when the forum main page shows two identical thread titles by the same person, on here, one in the Pally forum. Just a warning, as some mods are reliably strict on the rules. Take a look at them, for your own self preservation.
~Bails