This quest titled “Bomb Them Again” is a bit of a nuisance, yet fun.  After talking to Sergeant Vanderlip, go to the north of Ogri’la to Forgecamp: Wrath.  Legion Flak Cannons will start shooting fel fireballs at you.  Imagine you are in a arcade game.  You have to fly on your mount throwing bombs at the ammo piles, while maneuvering to dodge the fireballs.  They are pretty intelligent and will go straight at you, unless you make a sudden change of course.  Do not throw the bombs directly to the cannons.  It will do nothing. Focus on the ammo piles that are nicely marked by a redish-glowing hunter mark.  Once you destroy 15 of them, return to the NPC for a 11 gold 99 silver reward.  Watch the video.