I bought my Mossberg 835 in NC and have lived in PA for 4 years. since i have been in college i have not had any opportunities to use it and i wish to sell it.

What are the laws in PA conserning person to person gun sales. Do they had to be done at a shop or other facility? how are background checks done on buyers?

I am interested in selling the firearm since i have no need of it while in school.