Yeah but... why would criminals give ass about gun laws? They're criminals. Breaking the law is kind of their thing. Instead of legally getting gun licence and buying guns, they'll probably get one from a shady dealer or work with an organization that hands them out... At least how it's done in the movies.
Actually, organized criminals in Asia do give a damn about laws.
They have the best lawyers to make sure their organization's still running.
They do use guns but not openly.
Using guns in public are considered taboo for organized criminals.
It's to shield their senior leaders from criminal responsibility since it could lead to death sentence.