.410 Bore - Wikipedia

The small size of the .410 bore makes it popular for use in compact firearms carried for emergency use, and it is often found in over-and-under combination guns, with a .22 Hornet or .22 rimfire rifle barrel mounted above and a .410 bore shotgun barrel mounted below.

The Snake Charmer is a .410 bore, stainless-steel, single-shot, break-action shotgun with an exposed hammer, an 18+1⁄8-inch (460 mm) barrel, black molded plastic furniture, and a short thumb-hole buttstock that holds four additional 2+1⁄2-inch (64 mm) shotgun shells. These light-weight 3+1⁄2-pound (1.6 kg) guns have an overall length of 28+1⁄8 inches (710 mm).[8] They are commonly used by gardeners and farmers for pest control. It originally sold for $89.95 and was marketed as a general-purpose utility shotgun "perfect" for "fishing — hunting — camping — back packing — survival — home defense — truck or Jeep gun".

The Savage Model 24 is an American-made, over-and-under, combination gun, manufactured by Savage Arms. The basic .22LR over .410 bore model weighs 7 pounds (3.2 kg), has 24-inch (610 mm) barrels, and an overall length of 41 inches (1,000 mm). It may also be disassembled for ease of stowage. Its predecessor was made by Stevens and sported a tenite stock and forearm. In WWII, 15,000 were ordered and issued in air crew survival kits for Army Air Force bomber crews to be used as survival arms in the event that they were shot down.

The M6 aircrew survival weapon was made for the US Air Force, with a .22 Hornet rifle barrel mounted over a .410 bore shotgun barrel and was first issued in the Korean War. The military also lists an aluminum .410 3-inch (76 mm) shell, with a rifle primer, as standard issue under the ammunition inventory name M-35. The civilian version Springfield Armory M6 Scout has a .22 rimfire or .22 Hornet over a .410 bore shotgun barrel. The original M6 has a 14-inch (360 mm) barrel, the same length as the stock, and folds in half for storage, making a compact package. With the short barrel, this is legally classified as an any other weapon in the United States, so the M6 Scout is made with 18.5-inch (470 mm) barrels for civilian sales.[9] Special flare cartridges in .410 were issued with the USAF model.