Bill Of Sale
NOTE: Under Federal law, you CANNOT sell any firearm to a person who is not a resident of Utah in a private party transaction, unless a Federal Firearms Licensee (a gun store) performs the transfer.
It is HIGHLY recommended that you use a bill of sale and that you verify the person buying or selling the firearm is a Utah resident with valid identification. As of March 2013 you are allowed to perform a private party transfer via a local FFL if you wish. The only records created are held privately by the shop and yourself, and there is no waiting period once the background check is completed.