What's I find funny about this clip is that if you pay attention when the barrel flips around, they animated which end was the muzzle and which was the breech. Every time it fired, the animators correctly depicted the shot coming from the muzzle.

Except for the end, when he fired the last shot at himself from the breech end, because toon logic always requires the funniest outcome.

Knowing DIO and the fact that he had at least 4 children with different mothers, he would 100% fall for Bug's cross-dressing trick.