many non-restricted and restricted firearms can be converted to "clear the room" in 10 minutes. Some firearms you do something very simple like change firing pin spring, or make slight modifications. I'll go with the "no rhyme or reason" just like most prohibs. kind of like how shotguns that can switch from pump to semi like franchi SPAS and some benellis are prohibs. no rhyme or reason. well i guess you could scare someone to death with an SPAS!
This ease of conversion trash is just a red herring. "Change the firing pin spring"? Really? Do some serious design research. Some firearms can be converted without a major rework. Some are just about impossible to convert without remanufacture.
The whole thing was based on appearance and social engineering.