(Let's audience laughter die down.)
Philadelphia is in for a world of hurt. As recently as 1996, the Pennsylvania Supreme Court ruled on the issue of Philly's ability to regulate firearms.
"The right of the citizens to bear arms in defense of themselves and the State shall not be questioned.[*287] Because the ownership of firearms is constitutionally protected, its regulation is a matter of statewide concern. The constitution does not provide that the right to bear arms shall not be questioned in any part of the commonwealth except Philadelphia and Pittsburgh, where it may be abridged at will, but that it shall not be questioned in any part of the commonwealth. Thus, regulation of firearms is a matter of concern in all of Pennsylvania, not merely in Philadelphia and Pittsburgh, and the General Assembly, not city councils, is the proper forum for the imposition of such regulation."
Ortiz v. Commonwealth, 545 Pa. 279 (1996) at 286 - 287 (emphasis added). (The first line in the above excerpt is Article I, Section 21 of the PA Constitution.)