less Larger pellets means fewer pellets, resulting in a reduced probability of hits Heavier loads produce more recoil and greater velocity than lighter loads Reduced recoil loads (less shot and/or lower velocity) may produce smaller patterns, which may decrease hit probability Ammunition The most common type of ammunition used in combat shotguns, whether for military or law enforcement purposes, is buckshot, typically a 70 mm (2 inch) 12-gauge shell loaded with nine hardened 00 buckshot, with a diameter of about 8.4 mm (.33 inch). Buckshot is brutally effective at close ranges against unarmored targets—enough so that Germany issued a protest against its use in 1918. The only other types of ammunition currently in use in military shotguns are breaching rounds, which are either specially designed frangible rounds designed to destroy a door lock or hinge while minimizing the risk of damage to occupants of the room or very light (#9) birdshot, which accomplishes the same purpose. Shotgun slugs are currently under consideration by the US military as an anti-materiel round; the tendency of typical commercial shotgun slugs to deform on impact would render them illegal under the Hague Convention of 1899 and so a jacketed, hardened or sabot slug may be adopted. Less lethal rounds are used by U.S. troops serving as police forces in occupied territory; beanbag and rubber bullet rounds are commonly used to discourage looters and rioters. In military use, flechette ammunition has also been used in shotguns (primarily by special forces, such as its use by the SEALs in the Vietnam War), but this is not common. Other experimental shotgun ammunition has been created, such as SCMITR, but none have been successful enough to be adopted. Due to the great flexibility of the shotgun, it is often used in non-offensive roles as well. The US Infantry, for example, offers a number of less lethal varieties of ammunition for use in the riot control role, and for door breaching with #9 birdshot, shotgun slugs, and specialized breaching rounds. Less-lethal options also include the use of grenade launching cups, special launching cartridges and a less-lethal grenade. There are a number of experimental rounds currently under development and consideration by the US military, including explosive rounds and stand-off breaching rounds, which could further improve the range and flexibility of the combat shotgun. Method of operation There are two primary modes of operation for combat shotguns, the pump action, and