In light of a recent Pa. state supreme court decision affirming preemption in a matter involving a drug and narcotics issue where phila. oversteped their authority, Philadelphia counsel would be wasting their time even attempting to pass an ordinance going beyond the dictates of the uniform firearms act.
As far as preemption relating to state firearm laws, Ohio state supreme court recently affirmed the preemption laws in that state. This prescedent does not look good for the hacks that have run Phila. into the ground.