I had a similar idea, but with a turret similar to the Thunder (long range and medium damage), that could shoot through one layer of walls. The animation would be a small black orb issuing from the barrel followed by a larger shot; the small orb would make a hole in the wall or cover and the shot wot would pass through. This concept might also work with a short to medium range gun that caused high damage. With shorter range, this would be accompanied with a higher speed, and a moderate reload time (railgun?). It would unlock at the rank of Master Corporal.