During the mid 60's my family had a cottage on the beach in Destin. We were under the approach path to Eglin and several times each day I would see planes fly over, fairly low most of the time. The B-58's and B-52's were especially awesome. I built models of all of them.
Yes I too attended several of those firepower demonstrations. Great entertainment. I think they always started with the machine guns. Actually I think they must have intentionally slowed down the first one as it was just pecking along at what must have been around 200 rounds per minute.
I remember one year when they launched a sidewinder at another missile and it dove right into the ground. The announcer said they were heat seeking and the ground was too hot. They tried again and this time it worked.
One funny thing is he said the missile was so sensitive it could lock on a lit cigarette. After that, I noticed several people putting out their cigarettes.