Just to be silly:-
Before Michael Ryan went ape in Hungerford and gave Thatchler her chance to pass a disarming act, a friend of mine* had an ex-British Army Vickers Machine Gun converted to semi-automatic, in 7.92 mmm** calibre, with a smoothbored barrel held on a shotgun licence.
Ah well, very little chance of that being used in a bank job!.

It's all in the way the rules are interpreted

W


* A re-enactor
* It went from the British to the Israeli Army, fairly early on.