Truthfully, given the dependence of this design on the availability of a specific, not-particularly-common, centerfire cartridge, I don't see this as all that big a deal. The lunatic anti-gun nuts are already talking about the necessity for clamping down on ammunition availability. And we've all seen the empty shelves.
I'd be far more interested in a design that worked with black powder. Or, in case of future restrictions on commercial powder, with improvised propellant mixes - both KNO3 based, and alternatives - KCL03, NaCL03, KMnO4, etc.
I'd love to see a YouTube of one of these things being fired using a propellant mix worked up in a kitchen from ordinary table salt and sugar.
That'd cause some serious knicker-twisting.