Miniature calibre (caliber) adapters and conversions
Shoot any round through any firearm with subcaliber adapters - Carolina Sportsman
Miniature calibre (caliber) adapters and conversions
Could the use of 'adapters' which fit into the chamber and swapping of the bolt, extractor and other parts allow firearms to use different calibers as long as the new cartridge is
Caliber conversion sleeve - Wikipedia
26.5 mm to 22 lr Ammo Sub-Caliber Flare Gun Insert | FTF Industries Inc Firearms Parts & Accessories