آموزش نظامی و تفنگها

A Winchester M1897, one of the first successful pump-action shotgun designs

In pump-action shotguns, a sliding forearm handle (the pump) works the action, extracting the spent shell and inserting a new one while cocking the hammer or striker as the pump is worked. A pump gun is typically fed from a tubular magazine underneath the barrel, which also serves as a guide for the pump. The rounds are fed in one by one through a port in the receiver, where they are lifted by a lever called the elevator and pushed forward into the chamber by the bolt. A pair of latches at the rear of the magazine holds the rounds in place and facilitates feeding of one shell at a time. If it is desired to load the gun fully, a round may be loaded through the ejection port directly into the chamber, or cycled from the magazine, which is then topped off with another round. Well-known examples include the Winchester Model 1897, Remington 870 and Mossberg 500/590.

Pump-action shotguns are common hunting, fowling and sporting shotguns. Hunting models generally have a barrel between 600–700 mm (24"-28"). Tube-fed models designed for hunting often come with a dowel rod or other stop that is inserted into the magazine and reduces the capacity of the gun to three shells (two in the magazine and one chambered) as is mandated by U.S. federal law when hunting migratory birds. They can also easily be used with an empty magazine as a single-shot weapon, by simply dropping the next round to be fired into the open ejection port after the spent round is ejected. For this reason, pump-actions are commonly used to teach novice shooters under supervision, as the trainer can load each round more quickly than with a break-action, while unlike a break-action the student can maintain his grip on the gun and concentrate on proper handling and firing of the weapon.

Pump action shotguns with shorter barrels and no barrel choke (or very little) are highly popular for use in home defense, military and law enforcement, and are commonly known as riot guns. The minimum barrel length for shotguns in most of the U.S. is 18" (457 mm), and this barrel length (sometimes 18.5"-20" (470–500 mm) to increase magazine capacity and/or ensure the gun is legal regardless of measuring differences) is the primary choice for riot shotguns. The shorter barrel makes the weapon easier to maneuver around corners and in tight spaces, though slightly longer barrels are sometimes used outdoors for a tighter spread pattern or increased accuracy of slug projectiles. Home-defense/law enforcement shotguns are usually chambered for 12-gauge shells, providing maximum shot power and the use of a variety of projectiles such as buckshot, rubber, sandbag and slug shells, but 20-gauge (common in bird-hunting shotguns) or .410 (common in youth-size shotguns) are also available in defense-type shotgun models allowing easier use by novice shooters.

A riot shotgun has many advantages over a handgun or rifle. Compared to "defense-caliber" handguns (chambered for 9mm Parabellum, .38 Special, .357 Magnum, .40 S&W, .45ACP and similar), a shotgun has far more power and damage potential (up to 10 times the muzzle energy of a .45ACP cartridge), allowing a "one-shot stop" that is more difficult to achieve with typical handgun loads. Compared to a rifle, riot shotguns are easier to maneuver due to the shorter barrel, still provide better damage potential at indoor distances (generally 3–5 meters/yards), and reduce the risk of "over penetration"; that is, the bullet or shot passing completely through the target and continuing beyond, which poses a risk to those behind the target through walls. The wide spread of the shot reduces the importance of shot placement compared to a single projectile, which increases the effectiveness of "point shooting" - rapidly aiming simply by pointing the weapon in the