What is the highest gun caliber in the world?

Answer 1

Caliber is the term used for the diameter of the inside of the barrel (in shotguns, it is called gauge instead). The larger the opening of the barrel (known as the bore) the higher the caliber- but not necessarily the energy of the cartridge. The .600 Nitro Express was a VERY large cartridge used for VERY big game hunting- elephants. But it is an older, straight sided cartridge. The .50 BMG, while firing a skinnier bullet, has more energy. The largest rifle made for sporting use was probably the .700 Nitro Express, however, military anti-tank rifles (fired from the shoulder) have been as large as 20 mm- about .80 caliber. Some muzzle loading black powder weapons fired a 1 inch, or 1.00 caliber bullet. The king of the BIG bore is probably the Paradox- these were part rifle, part shotgun- that were measured in gauge rather than caliber. The largest, the 2 bore, fired a slug about 40 mm in diameter- or 1.600 caliber.