The Pittsburgh law does not just restrict the discharge of firearms within city limits which, I agree, a semi-defensible argument may be made that such a restriction does not undermine preemption. I have not gotten my hands on the text of the new legislation. However, it is reported that:
“The Pittsburgh legislation restricts military-style assault weapons like the AR-15 rifle authorities say was used in the synagogue attack. It also bans most uses of armor-piercing ammunition and high-capacity magazines, and allows the temporary seizure of guns from people who are determined to be a danger to themselves or others.”
Full Article:
https://www.google.com/amp/s/www.mcall.com/news/pennsylvania/mc-nws-pa-pittsburgh-mayor-gun-charges-blocked-20190412-lj5kewegbjfdnnfrkjjbnfbymm-story.html?outputType=amp
I argue that limiting magazine capacity, restricting firearm types, and restricting ammunition types is a clear and blatant violation of preemption. Specifically, PA preemption states that “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.” See the link below for full text:
https://www.legis.state.pa.us/WU01/LI/LI/CT/HTM/18/00.061.020.000..HTM
Furthermore, the district attorney warned the mayor and council before the legislation’s passage that enacting sic legislation could result in criminal charges for having violated preemption. Apparently, the DA is now saying that he will only consider filing charges against the mayor and/or council when 1) the laws go into effect and 2) someone is cited for having violated the law.