Hotz,
The standard kit on an AH-1G had one minigun (M134) in the turret, alongside a 40MM grenade launcher. Both were fed from an ammo bay right behind the turret, with slide-out drums. The minigun held 4000 rounds and the "chunker" held just over 300. The wing stores usualy held rocket pods, most often 19 shot inboard and 7 shot outboard. On the Cobra I mentioned, the turret had 2 miniguns, and the inboard wingstores had two XM-18 minigun pods (which held 1500 rounds each in a special de-linked electric feeder.
A few birds had the XM-35 20mm gun on the left inboard station, and saddlebag ammo bays on both sides of the fuselage. A fine gun, the last snake I flew had one, we called it "Mighty Mouse" and the crew chief painted some great nose art on it.
Like Bsouza says, the miniguns could jam fairly easily, I kept a few new bolts in my leg pocket along with a tube of LSA lubricant (monkeycum), and could rebuild a gun in a few seconds if it jammed badly.
The guns were accurate, and deadly. I took the tile roof off a house once, it tossed tiles all over the place.
The weapon that told the real story was the 2.75" rockets. They packed a punch, had relatively long range (accurate at 2-3 clicks, deadly at 1 click), and we carried enough to do some damage. The 10 lb warhead was standard, we had a 17 pound warhead, and a 10 lb VT fused version (a white round radar in the nose set it off a few meters above ground, for better effect). Each round hit like an artillery round, so with 52 to 72 rockets per Cobra, a pair of snakes could deliver about as much firepower as an artillery battery could toss out in an hour.