The .56 caliber smoothbore is a small game shotgun. It will also shoot roundball. It would be a 28 gauge approximately. I never owned one, but I do own a couple smoothbores. They are fun to shoot.

One thing about the smoothbore (and this is ONLY my experience). I bought one when I heard people brag of their accuracy out to 75 yards shooting roundball. That distance, being more then enough for me, I figured, why not.. So I got a .62 caliber smoothbore. While it makes a good shotgun for squirrel and rabbit, a roundball shooter it is not. Out to 40 yards it is pretty good. I have tried loading that roundball about every way you can think. One time it shoots good, next time out, all over the place. Out to 35 yards, it would be deadly with hunting accuracy lets call it. Past that, I have missed a 8x11 sheets of paper. I was shooting 100 yards one afternoon with it, and could not hit a cardboard box, so I aimed under the box and finally managed to put a hole in the box.

If you want a good squirrel shotgun or rabbit, it could be a lot of fun. I have grouse hunted with my .62 caliber and it makes a heck of a sport out of it with the only one shot. I now have two 12 gauges as well.