The new Remington Buckhammer is supposed to be for rifled barrels, but it looks as if it might work in a smooth bore, but haven't tried 'em. The Brenneke is the smooth bore alternative of choice, more down range energy, good accuracy. I haven't actually TRIED 'em, but just going on what I've read. I have a bunch of foster slugs in 12 and 20 just because. I've fired 'em at 50 yards and they're accurate to that range. Sometimes I carry a twice pipe when I'm small game hunting with a shot load in one barrel and a foster slug in the left in case I happen upon a hog. I sorta think of my doubles as combo guns with this capability. A slug could slap a hog pretty good out to 50 yards, 12 or 20 gauge, but the 12 has more horsepower of course. The only think I've found in a double is, you have to hold a little off to account for the regulation of the barrels, but once you know this, it's easy to keep 'em into 2" at 50 yards even with just a bead sight. Wouldn't worry about anything any further, though.