Am I correct to assume polishing the firing pin would be illegal?
In order to make this law work, they'd have to force manufacturers to build guns that make access to the firing pin difficult or impossible. That would require a redesign of almost all existing semiauto guns, and may actually be impossible in many designs. They would also have to have some sort of tamper indicator system. Obviously, this law would be rough on gunsmiths, but I don't think they care.