Well, we figured that out quickly and muountedva 20 mm pod under the "d" model. The "E" had an internal gun. I was one of five lucky guys to fly a one of a kind configured E that we mounted two 20 mm pods under the wins plus the internal gun and flew single ship into north Vietnam as an armed fast fac. There is actually a website dedicated to the five of us and the aircraft. I being the youngest of the five flew the most missions . We flew at approx 100 feet and above 500 k. It was also a great platform for wiporking search and rescue. Fly that one day and chase mugs in a clean bird the next or go bombing . Yes the F4 was a great warbird.