Shooting shotguns in Multigun competitions or 3-gun is all about the reload. The shooter that can reload faster than the others is gonna have an edge. This where shot shell carriers come into play. I use a combination of carriers, California Competition holder, the AP Custom holder (both seen in this video) and a side saddle mounted on the receiver of my shotgun. The AP custom is really nice but you need to make the decision if the double stack holder is right for you. The double stack properties come into play if you have to go prone while shooting. The added thickness may cause you trouble depending on where you have it mounted.