You can earn the Damage Control achievement by either dishing out 300000 points of damage or healing 300000 points of health. Now you could always just grind AV in the hopes of getting lucky and having the game last long enough.
I think my way is a little easier but no less frustrating. Warsong Gulch will continue to be the undisputed stalemate of BGs for a long time to come even at level 80.

[...] Undisputed Method of Earning Damage Control talks about how a healer can get 300k damage or healing to obtain the “Damage Control” achievement. [...]
[...] was the bg of choice for him, so in the middle of the second one I mention that I read Matticus’ Undisputed Method of Earning Damage Control and he said, “Hey, this will go long enough you could probably get it.” And I did. I [...]