18 PA.C.S. § 6120 states, "No county, municipality or township may in any manner regulate the lawful ownership, possession, transfer or transportation of firearms, ammunition or ammunition components when carried or transported for purposes not prohibited by the laws of this Commonwealth." This type of language is known as a Preemption Clause and denies all counties, municipalities and townships from regulating the ownership, possession, transfer or transportation of firearms or ammunition.
Some may recognize that this section has recently been in the news in regards to several laws that the city of Philadelphia passed limiting the types of firearms that could be owned, as well as, other regulations on firearms ownership. For a discussion of the recent Philadelphia regulations, which are invalid, as well as other regulations in violation of 18 PA.C.S. § 6120.
Another interesting aspect to 18 PA.C.S. § 6120 is its limitation on right of action against gun and ammunition manufacturers. " No political subdivision may bring or maintain an action at law or in equity against any firearms or ammunition manufacturer, trade association or dealer for damages, abatement, injunctive relief or any other relief or remedy resulting from or relating to either the lawful design or manufacturer of firearms or ammunition of the lawful marketing or sale of firearms or ammunition to the public." (18 PA.C.S. § 6120). However, "Nothing in this subsection shall be construed to prohibit a political subdivision from bringing or maintaining an action against a firearms or ammunition manufacturer or dealer for breach of contract or warranty as to firearms or ammunition purchased by the political subdivision." (18 PA.C.S. § 6120)
To fully understand the limitations, one must look to the definition of a "political subdivision." A political subdivision is defined as "any home rule charter municipality, county, city, borough, incorporated town, township or school district." (18 PA.C.S. § 6120). Furthermore, a dealer is defined as "any person engaged in the business of selling at wholesale or retail a firearm or ammunition." (18 PA.C.S. § 6120). Moreover, "firearms" is to have the meaning given to it in 18 PA.C.S. § 5515 (relating to prohibiting of paramilitary training) but shall not include air rifles as that term is defined in 18 PA.C.S. § 6304 (relating to sale and use of air rifles).