Just did it for the first time. Was offline, solo. I'm level 30. All I used was this strange machine gun thing I had that fired slag type lasers, a slag sniper rifle, some corrosive transfusion grenades, and this shock smg thing I had. I took bunker itself out with just the machine gun thing and the sniper rifle. It was actually ridiculously easy. didn't even die once either.
On another not, I got the purple class mod that I needed from the stuff it dropped. So cheers who mentioned bunker in my other topic.