Not sure if this is a widespread Issue, but i did not get any Progress by using the normal VD-12, only Akimbo progressed the Achievement for me.
From my personal Experience, these are the best maps to get lots of Kills fast:
-Counterfeit
-No Mercy
-Undercover
On Undercover and Counterfeit you might have Issues with Snipers if you dont bring the right Secondary!