Charles Daly // 12GA Gun Gauge Adapter Rifled Insert 40S&W/7"BBL
Short Lane Gun Adapters Stack-N-Pack Kit: Turning a 12 Gauge into a Truly Versatile Weapon
Rifled Shotgun Adapter 12 Gauge to 9mm - Gunadapters.com
Eagle Gun Range -Macon GA - X-Caliber Ammo Adapter Set for Shotguns. It's an 8-piece set of drop-in adapters that measure seven inches long each, and it comes with a carrying case.
Rifled Shotgun Adapters - Gunadapters.com
12GA to 357 Magnum Shotgun Adapter - Chamber Reducer - Stainless - Free Case !!! | eBay