No gun sweeter than a 0.50 cal, though I love all of the gatling variants almost as much (20 mm Vulcan, 7.62 mm minigun, etc.).
I missed a chance to fire a 0.50 cal while I was in the Navy. I didn't realize it was people I knew firing it. After they were done firing, I passed one of the gunners in a passageway and he said I should have come down and asked to shoot

But I got the ammo box and a linked belt of shell casings.