“Haven’t they ever heard of changing out the firing pin?”
That would be an easy thing to do, but one thing you notice is that criminals tend to be rather stupid.
My point is that the law would be completely ineffective at preventing circumvention by the very nature of firearms. The proponents are moving in for a rhetorical kill that is simply the setup to eventual confiscation - after all, if the other laws didn’t work, then perhaps taking away the gun WOULD!
Just buff the end of the firing pin with some 400 grit emery cloth and the problem is solved.