The Pennsylvania Attorney General has unilaterally overturned a duly passed state law and declared an 80% receiver to be a firearm.
AG Shapiro, Gov. Wolf: 80% Receivers Are Firearms
All this over something that is used in a tiny, tiny fraction of ARs, which are used in a very small percentage of gun crimes. Tempest in a teapot.
This is just one step removed from declaring raw aluminum bauxite (the most common aluminum ore) a firearm.