Weird gun laws create weird workarounds. Everybody is no doubt familiar with the product of the bazaars of the Khyber Pass, the village smithies of Mindanao, and the basement machine shops of Belfast.
In places where guns are quasi legal, legitimate manufacturers will often build quasi-guns. Witness, for example, this Hungarian double-barreled, over-and-under, slide-action, breech-loading, rubber-bullet-launching shotgun-type thingummy. I'd rather have an 870, but given the legal restrictions under which it exists, it sure beats a handful of nothing, plus it practically oozes ingenuity.
The only thing that would make it better is if it had a bayonet. Or if it launched bees. (Preferably African killer bees, but regular old honeybees would do in a pinch.)