Instant shot that deals 50% of ranged weapon damage and Silences the target for 3 seconds.
Silencing Shot is a instant shot that deals 50% of ranged weapon damage and silences the target for 3 seconds. It will interrupt spells being cast even if the target is immune to silence effects. The shot is off the global cooldown, allowing it to used "in between" other shots. This has the side effect of making Silencing Shots a DPS increase even against targets who are not spell casters, as it deals damage without triggering the global cooldown.
Many monsters, instance and raid bosses in particular, are immune to silence effects. Some are also immune to interrupts. Silencing Shot will still deal damage to them, and so is still worth using if you can spare the mana.
Does not share a cooldown with any other hunter abilities.
The silence effect is considered to be an Arcane-based effect, meaning that mobs which are immune to Arcane magic will be immune to the silence effect. They still take full damage, however, as the shot deals physical damage.
Can be used to force caster mobs to move, as they will usually try to enter melee range when silenced. This can be useful to get them to walk onto traps or to get them into a bigger group of mobs so that you can use Volley on all of them. This is especially useful in instances.
If nothing needs to be silenced during a fight, you can use Silencing Shot as soon as it comes off cooldown to increase your DPS. This will however cost a significant amount of mana.
Especially useful to prevent healers from healing your target in PvP, buying you a few extra seconds to get that Kill Shot off.
Patch 3.2.0 (2009-08-04): This ability will also apply a 3 second interrupt effect against non-player controlled targets, making it more versatile against creatures immune to silencing effects.
Patch 3.0.2 (2008-10-14): This spell will now interrupt the current spell being cast on the target and lock out that school for 3 sec if the target is immune to silence effects.
Patch 2.0.6 (2007-01-23): Silencing Shot now does only 50% of weapon damage instead of 75%.
Patch 1.7.0 (2005-09-22): The tooltips for quick Hunter shots have been updated to show them as instant abilities.
Patch 1.5.0 (2005-06-07): Special ability shots no longer add the ranged weapon speed or take into account ranged weapon haste when determining the actual cooldown. The tooltip and cooldown timers should now properly reflect the actual cooldown.
Edit
Patch 3.2.0 (2009-08-04): This ability will also apply a 3 second interrupt effect against non-player controlled targets, making it more versatile against creatures immune to silencing effects. 
Patch 2.0.6 (2007-01-23): Silencing Shot now does only 50% of weapon damage instead of 75%. 
