And the US.
For a modest price, you too can build your own tank gun suppressor.
https://apps.dtic.mil/dtic/tr/fulltext/u2/a241063.pdf
The original construction of the device for its intended use would of have to have been a suppressor, not a car. So the fact it was never form 1'd with a serial from origination makes it a non transferable, non NFA item. You are now in possession of an illegally manufactures suppression device.