Expert Timing

You can solo this at 110 by pulling all the Ogron while mounted. This will line them up. Jump in the Iron Star and they'll all drop aggro, but you can still fire the Iron Star and hit them while they evade to get the achieve. I just did this on my rogue.

Just completed this in one attempt.

Use the farthest star as you enter the dock area.
Shift your aiming arrow a bit to the left to line up dead center on the 3rd stationary Ogron.
The 4th pats back and forth rapidly. My 1st and 2nd were pretty much lined up after 2 minutes of waiting.
Release the star just as 1 and 2 are coming in to stop in line with 3 AND when 4 is just starting to pat from left to right.

This timing gets 1 and 2 before they leave and 4 as it runs in (3 is a given since we're lining up off that)

To earn this achievement you have to visit [zone=6951] instance, slay [npc=81305] to make iron stars usable. Take that one, which is next to a wall and wait. Each eight mintes all four ogrons line up and there's a chance to hit them all with a singe star.
You also may pul them all, jump into the star and hit them while they're evading, works well too.

Achievement is a part of Glory of the Draenor Hero.

Expert Timing — https://www.youtube.com/watch?v=7f5qvmAYoGM
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[zone=6951] achievements list

Expert Timing

https://www.youtube.com/watch?v=7f5qvmAYoGM

Militaristic, Expansionist

https://www.youtube.com/watch?v=LEGJMG38Yho

Take Cover!

https://www.youtube.com/watch?v=Ad02fz_wNWc