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.
X-Caliber Shotgun Gauge Adapter System
12 Gauge Adapters
12GA to 357 Magnum Shotgun Adapter - Chamber Reducer - Stainless - Free Case !!! | eBay
X-CALIBER Survival-Rifle Gauge Adapter System - Soldier Systems Daily
Chiappa Inserts Let You Convert a Shotgun for Other Gauges and Centerfire Cartridges
The Utility of 12-Gauge Caliber Adapters, The Good, Bad, & Ugly -The Firearm Blog
Short Lane Gun Adapters Stack-N-Pack Kit: Turning a 12 Gauge into a Truly Versatile Weapon
The Utility of 12-Gauge Caliber Adapters, The Good, Bad, & Ugly -The Firearm Blog
X-Caliber Shotgun Gauge Adapter System
What are Shotgun Adapters? - Shotgun Adapters - https://chaszel.com
Charles Daly // Accessories
12ga to 38special adapter at 50 yards - YouTube
12ga to 22LR rifled shotgun adapters Gunadapters - YouTube
Does anyone have experience with these? (shotgun caliber adapters) : r/guns