 Police trade-ins are a great way to get, you know, a gun that's in good condition. And so most people, if they're looking for a deal, that's something that they definitely would consider. Still, Mark says one of his daily duties as a reputable dealer is to sniff out risky customers, no matter what kind of gun he's selling, to make sure that none of his products end up as one of the more than 400,000 guns recovered yearly in crimes in the U.S.