Amazon.com : AGGXPF Bright red/Green Laser Bore Sight Kit for .17to12GA Caliber, Laser Boresighter Kit with 12 Multiple Caliber Adapters, Laser Bore Sighter for Hunting Zeroing Your Scopes Optics (Green Laser) :
Amazon.com : StrongTools Plastic Adapters Universal Red and Green Boresighter Suitable for .17 to 12GA Calibers (Universal Adapters, 2 Packs) : Sports & Outdoors
20GA to 357 Magnum & 38SPL RIFLED Shotgun Adapter - Chamber Reducer - Stainless Steel
EZshoot Boresighter's Adapters & Screws for 0.177 to 0.54 Caliber Bore