Sorry for the delay - was out of town for a bit...
Yes, the AC-130H had TWO 20mm gattling guns (2,000 rounds per minute each), one 40mm Bofors rapid fire cannon (100 rounds per minute), and a large 105mm cannon (about 3-5 rounds per minute). We COULD fire them ALL at once, and did on occasion, but not normally. In the combats I was in, we were used more as a "sniper" than anything. Since we were air - refuelable, we would fly for as long as the ammo lasted. Usually around 5-6 hours with a lot of loiter time which ground troops love overhead. Our main mission was mostly urban fighting at night - working with small units going through cities, etc.
It was fun flying the GUNSHIP because you got to shoot back.....flying the HERK doing airdrop was a fun challenge as well, but flying the Gunship was a real hoot!
BTW, we had NOTHING in terms of navigation and SA like we do now with IFly and STRATUX! It was so basic compared to what our OWN planes have now!
Your airline flying sounds like a lot of fun as well. I am sure you have a few dozen logbooks worth of great expereinces!
Here are some stock and personal photos from flying the AC-130H