This will sound tacky and I don't mean it to so apologies up front. In Oklahoma (and I presume Arizona) you can sell your own television, dog, rifle, pistol, etc. to another private party without papers. It's one of the privileges of living in a free country. With that privilege comes risk. Caveat emptor. If you have a question as to whether or not a firearm you're thinking about buying is stolen, I presume most any law enforcement officer would run a quick NCIC check on it by serial number. Takes less than a minute if NCIC is up. But even then, a lot of people don't record serial numbers. I think (and may be wrong) that most states have a similar law permitting private firearms sales in that manner. The bottom line is that you don't know if something's stolen when you buy from an individual. I'll accept the risk over additional government controls.