basically you need to start a new game for this to work. I bought the game at launch and tried many options to get this to poop to no avail. however I deleted my level26 character (me a sad panda), and started a NEW game from the menu.
amazingly my stash box still had gear in it rom my other characters even though they no longer exist! I took some grenades and went hunting, I found in the very early area of the game a point with 2 ticks and a runner and a bunch of cars, and as you can see from the footage below, this achievement now unlocks first time. I won this today at 14.11.
please like if you found useful. I would say that if this is your last achievement to get in the game then just delete all your characters and start again.