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X-CALIBER Survival-Rifle Gauge Adapter System - Soldier Systems Daily
X CALIBER Shotgun Adapter Field Test with Tim Ralston of National Geographic 's Doomsday Preppers - YouTube
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.
Chiappa Firearms - X-Caliber Shotshell-To-Cartridge Inserts Now Available Individually - Soldier Systems Daily