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
45 COLT to .22 LR Caliber Adapter - Chamber Reducer - Stainless Set of 6
Shoot any round through any firearm with subcaliber adapters - Carolina Sportsman
X-CALIBER Survival-Rifle Gauge Adapter System - Soldier Systems Daily
Runway Sub-Caliber Adapters for 26.5mm Flare Guns - YouTube
Why is there no subcaliber small arms ammunition? - Quora
X-CALIBER Survival-Rifle Gauge Adapter System - Soldier Systems Daily
Chiappa X-Cal 12 Ga Adapter Set of 8 Inserts Case
Caliber conversion sleeve - Wikipedia
Sub Caliber Adapters How? Why? - YouTube
X-Caliber Shotgun Gauge Adapter System - Athlon Outdoors
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 ...
Short Lane 12 Gauge/.22LR Sub-Caliber Adapters - YouTube
Gun Adapter
X-Caliber Shotgun Gauge Adapter System - Athlon Outdoors
X-CALIBER Survival-Rifle Gauge Adapter System - Soldier Systems Daily
20 Gauge Shotgun Adapter – AnytimeAmmo
Miniature calibre (caliber) adapters and conversions
Cartridge Adapters | An Official Journal Of The NRA