It isn’t unusual for competitive shotgunners to have either multiple barrel sets or to use barrel inserts in order to shot more than one gauge from a single shotgun. Once they get a particular gun dialed in with the balance and dimensions they like, those inserts or extra barrels allow them to seamlessly transition from 12 gauge to 20, 28, and .410.
But there’s another reason to consider this technology. You can convert a shotgun into a centerfire metallic cartridge firearm by adding inserts as well.
Chiappa’s X-caliber adapters slide into the breech end of a break-action shotgun barrel and are positioned so that the “rim” of the adapter lines up with the shotgun’s extractor.
They come sized for both 12- and 20-gauge shotguns. With a 12-gauge insert you can convert the gun to the following: 20 gauge, .410/.45 Colt, .45 ACP, .44 Rem. Mag., .40 S&W, .357 Mag./.38 Spl., 9 mm, and .380 ACP.
With a 20-gauge insert the following are options: .410/.45 Colt, .45 ACP, .357 Mag./.38 Spl., 9 mm.
Personally, I could see adding a .44 Rem. Mag. insert to my kit in order to have it for a backup hunting/survival round on backcountry bird hunting adventures. It’s an interesting piece of kit.