another good reason ..... I once bought a used Taurus 92 9mm it wouldn't shoot a group into a sheet of plywood never mind a one and a half inch group so I traded it off to a dealer. Later in that guns life it was used in a crime and left behind .... I know this because the paper trail led BATF to me asking some questions like did I own this gun and the answer was yes but I traded it to xyz on this date for ??? they were happy I had the records and they went further down the paper trail.