You want to reread that first paragraph which reads "The defensive tail
armament was changed. The quartet of 0.50-inch machine
guns carried by earlier versions was replaced by a single General Electric
M61 20-mm six-barreled rotary cannon. "

Ahh, I see. I read it to infer that the replacement was made post production.


BUFDRVR

"Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips
everyone on Bear Creek"