While leveling my engineering on my alt i realized that you can use the High-Powered Bolt Gun at level 65.
Im sure most people don't realize this, and with its 6800 to 10200 damage its really ****ing OP in pvp as most people don't have over 8k hp at that level
All you need to do is level engineering to 450 when you hit 65 and buy the High-Powered Bolt Gun from AH or have someone make one for you, as you need 465 to make it, but only 450 to use it!
It also works like a grenade, so it can hit many targets at once!
Here is a screenie:
EDIT: I just realized you can crit with it, even more epic damage