World War Z

Another level that is great and perhaps the best in doing just turrets is Episode 3: Moscow - Chapter Battle of Nerves. This chapter has 4 turrets throughout the level.

Just do an offline campaign with bots on easy or normal. The chapter is quite easy and can be ran through pretty quickly. Do the chapter 4 times to get the achievement.

The last part of the chapter is also a great way to boost your weapon levels as there is plenty of different weapons to choose from at the end and endless zombies keep coming. Once you complete turning all valves on and it wants you to turn on the final one, dont and let the zombies keep coming until your desire.

Episode 1 mission 3 Hell and High Water. Just over halfway through the level there is a spot to easily grab 2 turrents and 4 mine defuses for both this achievement and the "Waste of Time" achievement.

Fastest way I found (much better than the other solutions which take longer) was to select Episode 1 New York - Mission 4 Dead In The Water.

Within a minute of the mission you'll find 3 turrets to hack straight off the bat. Just head out to the street and follow the markers. It's by the water side in an office and then below on the train tracks.

I suggest doing it solo/offline mode.

Thanks

Friend of machines
Capture 15 turrets

There are a few missions that you can do this on. I like to use Episode 4, mission 2. This must be on insane. Play as the fixer class and run through the first part of the mission, before you get the the first door you will see land mines or turrets. If you see the turrets hack them, after that or if you see land mines just restart. This video will show you exactly what to do. I hope you enjoy.