Anyone ever seen one? Not me. At least not on the "Guns & Ammo TV" show the other day when they did their usual "Torture Test" segment of the show. They had a Bennelli 12 gauge and slipped a 20 gauge shell into the barrel then a 12 gauge/deer slug behind it and pulled the trigger. The only thing that happened was it sent the 20 gauge out as a projectile. Empty 12 gauge hull ejected. No damage to the gun. They were puzzled. Then they put a regular 12 gauge shell with shot behind the 20 gauge shell and tried it again. The gun fired, sending the 20 gauge hull out as a projectile and the 12 gauge hull ejected out onto the table with absolutely no damage to the gun. They were puzzled and only comment was: Hmmmm.... "I guess we're sending the wrong message out here"........... Pretty funny.