Runway Sub-Caliber Adapters for 26.5mm Flare Guns - YouTube
Shoot any round through any firearm with subcaliber adapters - Carolina Sportsman
these are shotgun adapters aka chamber reducers aka shotgun inserts and called by a few other names. they allow you to fire lower gauge (caliber) shotgun shells out of a larger bore gun. they are for use in break action type guns and won't (or shouldn't. i ...
Gun Adapter
The Utility of 12-Gauge Caliber Adapters, The Good, Bad, & Ugly -The Firearm Blog