A background check shouldn't take longer than 3 days, but if it does that gun should not transfer. This is a no-brainer. If you are going to transfer the weapon anyway, why even have the check? Or maybe the seller should be accountable for anything that is done with that weapon in the meantime? That would be a nice compromise for those that believe that only trustworthy people ever buy guns legally. Let them be tried as an accomplice in any crimes used by that weapon for transferring prior to the check completing.