If you happen to sell it to a "prohibited person", a person who is not allowed to own/have possession of a firearm, I am sure a lawyer will try to say that you are liable because you did not insure that the person buying was allowed to own/possess. That being said your defense is that PA law does not require you to do any kind of check on a face to face sale of a long arm. How this defense would stand up in a lawsuit would depend on how good your lawyer is. I agree, there should not be any jeopardy in the sale. But, the way people sue nowadays, you will have to spend money to defend yourself. Again, a big but, but even with a bill of sale that my not stop a lawsuit. The only way, from my view would be to do the transfer through an FFL and if the PICS comes back unapproved you only lost the sale to that person. If the PICS comes back approved I would think that you're off the hook for anything that happens in the future.
In a criminal case, if the firearm is used in a crime and they trace it to you and you say "well I sold it to some guy, I don't have any info on him and I don't remember his name", the police may then ask you to prove that it wasn't you that committed the crime. I just think it is easier to do a bill of sale. Now you may say that the buyer might give you a false ID, address, phone, etc. So be it, you still have the paperwork showing that you sold it to someone in good faith and that should help clear you of the crime.
All of the above being said it would probably be best to discuss this with a lawyer well versed in firearms law as we on the forum (with several exceptions) ARE NOT lawyers. We are only giving our opinions. And remember,
opinions are like a**holes, everyone has one and some are bigger than others.
