club banger

A small sub-compact pistol, easily concealable in any clothing.

Although not usually carried when going out clubbing, club banger describes the sort of pistol you could carry to a club, just in case something happens.

You want a smaller gun? You're gonna want this one. It's a nice club banger this. You won't go wrong with it; shoots straight every time.

He went out wearing a pair of golden shoes and a club banger in his belt.