Bipod

A bipod is a support device that is similar to a tripod or monopod, but with two legs. It provides significant stability along two axes of motion (side-to-side, and up-and-down.)
On firearms, bipods are commonly used on rifles to provide a forward rest and reduce motion. They are also seen on other long-barreled weapons, especially light machine guns or squad automatic weapons. Machine guns are capable of firing long continuous bursts of fire, but at the cost of increased recoil (which decreases accuracy), and increased weight (machine guns are heavier in order to absorb the stresses of prolonged fully-automatic fire). The bipod permits the operator to rest the weapon on the ground, a low wall, or other object, reducing operator fatigue and permitting increased accuracy.

A Sako TRG-42 sniper rifle on its standard factory bipod
Rifle or machine gun bipods can be of fixed or adjustable length. The better ones can be tilted and also have their tilting point close to the bore central axis, allowing the weapon to tilt a little left and right, allowing a quick horizontal sight picture on uneven ground and keeping the operator close to the ground. Bipods are for the most part folded away forward, not back towards the shooter.

Rifle

A rifle is a firearm designed to be fired from the shoulder, with a barrel that has a helical groove or pattern of grooves ("rifling") cut into the barrel walls. The raised areas of the rifling are called "lands," which make contact with the projectile (for small arms usage, called a bullet), imparting spin around an axis corresponding to the orientation of the weapon. When the projectile leaves the barrel, the conservation of angular momentum improves accuracy and range, in the same way that a properly thrown American football or rugby ball behaves. The word "rifle" originally referred to the grooving, and a rifle was called a "rifled gun." Rifles are used in warfare, hunting and shooting sports.
Typically, a bullet is propelled by the contained deflagration of an explosive compound (originally black powder, later cordite, and now nitrocellulose), although other means such as compressed air are used in air rifles, which are popular for vermin control, hunting small game, and casual shooting ("plinking").
In most armed forces the term "gun" is incorrect when referring to small arms; in the military, the word "gun" means an artillery piece or crew-served machine gun. Furthermore, in many works of fiction a rifle refers to any weapon that has a stock and is shouldered before firing, even if the weapon is not rifled or does not fire solid projectiles.
Rifles traditionally fired a single projectile with each pull of the trigger. Modern assault rifles are capable of firing in bursts or fully automatic modes, and thus overlap somewhat with machine guns. In fact, many light machine guns (such as the Russian RPK) are adaptations of existing assault rifle designs. Generally, the difference between an automatic rifle and a machine gun comes down to weight and feed system; rifles, with their relatively light components (which overheat quickly) and small magazines, are incapable of sustained automatic fire in the way that machine guns are. Generally the rifle is an individual weapon, while the machine gun is crew-served: that is, at least two soldiers are dedicated to carrying and operating it.

Medium machine gun

A medium machine gun or MMG, in modern terms, usually refers to a belt-fed automatic firearm firing a full-power rifle cartridge and typically weighs from 15 to 40 pounds (6.8 to 18.1 kg). MMGs usually have some type of provision for extended firing, such as a removable or extra-heavy barrel, cooling fins, or a water cooling jacket, but are light enough to be used with a bipod. They occupy a gray area between light machine guns and heavy machine guns.
Two features which have remained somewhat constant, however, are some added ability for greater fire over automatic rifles, and the ability to be used in both light infantry support roles on a bipod, but also on mounts and tripods. While heavy machine guns (HMG) are mostly fired from heavy mounts, and light machine guns (LMG) are usually operated with bipods, MMGs have historically been used in both. Heavy machine guns are either crew-served or mounted, while MMGs are usually operated by one to two soldiers. Light machine guns and automatic rifles are often an individual weapon with a fixed, naked barrel. On the other hand medium machine guns have usually had more endurance of some sort, such as the aforementioned heavier barrel, barrel-change, fins etc.

In the late 1800s, Gatling gun and other externally-powered types such as the Nordenfelt were often made in different ranges of calibers, such as half-inch and one-inch. Thanks to their many barrels, overheating was not so much of issue, and they were also quite heavy; being, essentially, heavy machine guns.
When Hiram Maxim developed his recoil-powered machine gun that used a single barrel, the first main design was a modest 26 pounds (11.8 kg) in weight, and fired a .45-inch rifle caliber bullet (from a 24 inch long barrel). As depicted in a famous photo of Maxim, it could be picked up complete with its 15 pound (6.8 kg) tripod with one arm. It was similar to present day (2005) medium machine guns, but it could not be fired for extended periods. As a result, he created a water jacket cooling system to enable it to fire for extended periods. This added significant weight, as did changes to more powerful cartridges. This class of heavy water-cooled machines gun would eventually be regarded as the classic heavy machine guns. However, the much lighter total weight possible by using recoil to power automatic loading was not lost on the firearms designers of the day. Soon there was a host of new automatic firearms that used this concept, such as the Borchardt pistol, the Cei-Rigotti rifle, the Madsen 1902, as well as lighter, gas-operated, air-cooled designs.

Light machine gun

A light machine gun or LMG is a machine gun that is generally lighter than other machine guns of the same period, and is usually designed to be carried by an individual soldier, with or without an assistant. Modern light machine guns often fire smaller-caliber cartridges than medium machine guns, and are usually lighter and more compact. LMGs are often used as squad automatic weapons.
There is confusion between what is a true light machine gun and what is a medium machine gun. Some weapons on this page, as written, are not in any way light machine guns (for example, the Browning 1919).
The term "light machine gun" is both literal and context-sensitive. Some machine guns - notably General purpose machine guns - may be deployed as either a light machine gun or a medium machine gun. As a general rule, if a machine gun is deployed with a bipod it is a light machine gun; if deployed on a tripod it is a medium machine gun (unless it has a barrel diameter of about 10mm or larger, making it a heavy machine gun).
Originally, the machinegun was the antithesis of infantry tactics, as was especially obvious in World War One and the high casualties of 1914 and 1915. It was obvious to several militaries that a light machinegun at the platoon or squad level would boost the firepower of infantry and allow them to suppress targets like enemy machinegun posts. By the end of the war, light machineguns were sometimes being issued on a scale of one per section or squad, and the modern infantry squad had emerged with tactics that were built around the use of LMGs.
It is possible to fire a light machine gun from the hip or on the move, but this is seldom accurate. They are usually fired from a prone position, especially when using a bipod. Early light machine guns (especially those derived from automatic rifles, such as the M1918 Browning Automatic Rifle) were sometimes magazine-fed. Some LMGs, such as the Russian RPK, are modifications of existing assault rifle designs. Adaptations generally include a larger magazine, heavier barrel to resist overheating, more robust action to support sustained fire, and often a bipod. Modern light machine guns are designed to fire more rounds of a smaller caliber ammunition and as such tend to use a belt of ammunition; this allows them to fire for longer periods of time without the need to reload. Other modern light machine guns, such as the FN Minimi, are capable of firing from either an ammunition belt or a detachable box magazine.

Daewoo USAS-12

The USAS-12 is an automatic shotgun designed as a combat shotgun made and developed in South Korea by Daewoo Precision Industries during the 1980s.

The USAS-12 is a gas-operated, selective-fire weapon which is designed to provide sustained firepower in close-combat scenarios. It accepts detachable 10-round box magazines or 20-round drum magazines. Both types of magazine are made of polymer, and drum magazines have their rear side made from translucent polymer for quick determination of the number of shot shells left. It has a range of 40m.
The latest version of the USAS-12 is capable of fully automatic fire.

The history of the USAS-12 shotgun dates from the 1980s vintage designs of Maxwell Atchisson. In about 1989, Gilbert Equipment Co. (USA) decided to bring up the selective fired weapon, broadly based on principles, employed in Atchisson shotguns. The design of the new weapon was produced by John Trevor Jr. Since Gilbert Equipment Co. had no manufacturing capabilities, it started to look for possible manufacturers. It turned out that the only maker that agreed to produce this weapon was the South Korean company Daewoo Precision Industries, a part of the high-tech Daewoo conglomerate. Daewoo engineers adapted the new weapon to their manufacturing techniques, and mass production commenced in the early 1990s. This gun sold well to military and security forces of several (unspecified) countries in Asia, and more than 30,000 of USAS-12 shotguns were made by mid-1990s. During the same timeframe, Gilbert Equipment Co. tried to bring semi-automatic version of USAS-12 to the U.S. market, but the BATF promptly classified this weapon as "having no sporting purpose", so it became a "destructive device" under the U.S. National Firearms Act of 1934. This greatly restricted its civilian use. During the late 1990s, RAMO Defence Co. began to assemble USAS-12 shotguns from Korean and U.S.-made parts for sale on domestic market, but sales of this weapon were limited to government agencies only. Today, this gun is still being manufactured by Daewoo in Korea for Military and Law Enforcement sales only. Recently, a US firearms manufacturer, Ameetec Arms LLC of Scottsdale, Arizona, has started the manufacture of a USAS-12 semi-automatic clone, called the WM-12; it mainly differs from the USAS-12 by the lack of fixed sights and carrying handle, replaced by a Picatinny Rail. The manufacturer states that the WM-12 is not a Destructive Device, and is thus readily available to civilians. As of January 2008, however, the WM-12 was no longer to be found on Ameetec Arms online catalogs due to the fact that it was discontinued after its initial semi-production run. Only a few WM-12s were actually built using USAS-12 Demilled shotguns.

Steyr TMP

The Steyr TMP (Taktische Maschinenpistole/Tactical Machine Pistol) is a select-fire 9x19mm Parabellum caliber machine pistol manufactured by the Austrian company, Steyr Mannlicher. It is renowned for its controllability, allowing a shooter to accurately fire the weapon in bursts of more than 10-15 rounds, instead of the typical two or three round bursts that other submachine guns are limited to. Magazines come in 15/30 round detachable box types. A suppressor can be also fitted. The Steyr SPP is the civilian variant of the TMP which has no foregrip and is capable of semi-automatic fire only.
In 2001, Steyr sold the design to Brügger & Thomet who developed it into the Brügger & Thomet MP9.

The Steyr SPP (Special Purpose Pistol) is a semi-automatic variant of the TMP. The TMP's barrel and barrel jacket lengths were increased slightly so there is a greater length of protruding jacket and barrel. The forward tactical handle was removed and a small spur installed instead.
The SPP is believed to have been created in order to fulfill the pistol portion of the XVII Land Warrior objective handheld personal defense weapon. It is somewhat large for a pistol and is constructed mainly from synthetic materials.

Cartridge

The cartridge case seals a firing chamber in all directions except down the bore. A firing pin strikes the primer, igniting it. The spark from the primer ignites the powder. Burning gases from the powder expand the case to seal against the chamber wall. The projectile is then pushed in the direction that releases this pressure, down the barrel. After the projectile leaves the barrel the pressure is released, allowing the cartridge case to be removed from the chamber.

An M4 Carbine, with an ejected case visible in mid-air.

Various cases of assorted common calibers.

Aluminum .44 caliber cases.
Automatic and semiautomatic firearms, which extract and eject the case automatically as a part of their operation, sometimes damage the case in the process of ejection. Brass is a commonly used material, as it is resistant to corrosion and ductile enough to be reformed and reloaded several times. However, some low-quality "plinking" ammunition, as well as some military ammunition (mainly from the former Soviet Union and China) is made with steel cases because steel is less expensive than brass. As militaries typically consider small arms cartridge cases to be a disposable, one-time-use affair, the lack of ductility is inconsequential for this application, although the mass of the case affects how much ammunition a soldier can carry. Some ammunition is also made with aluminum cases (see picture).
Critical specifications include caliber, bullet weight, expected velocity, maximum pressure, headspace, overall length and primer type. A minor deviation in many of these specifications could result in damage to the firearm, and in extreme cases injury or death of the user. The diameter of a bullet is measured either as a decimal fraction of an inch, or in millimeters. The length of a cartridge case may also be designated in millimeters.
Where two numbers are together, the second number can contain a variety of meanings. Frequently the first is the diameter (caliber) of the cartridge, and the second is the length of the cartridge case. For example, the 7.62 x 51 mm uses a bore diameter of 7.62 mm and has an overall case length of 51 mm. In the case of old black powder cartridges, the second number typically refers to the powder charge. For example, the .50-90 Sharps is a .50 caliber bullet (.512) with a nominal charge of 90 grains (5.8 g) of black powder with a case length of 2.50 inches (64 mm).
One should be aware that cartridge nomenclature is inconsistent and unhelpful when trying to determine dimensions, tolerances or indeed almost any other characteristic of a given round. The .38 Special actually has a bullet diameter of 0.357 inches (9.1 mm) (jacketed) or 0.358 inches (9.1 mm) (lead) while the case has a diameter of 0.380 inches (9.7 mm). The .357 Magnum is a direct evolution of the .38 special, but differently named, and no reference is made to the longer case. The .30-06 rifle round is a (nominally) .30 inches (7.6 mm) caliber round designed in 1906; and the .303 British round may vary wildly in actual dimensions (as do the surviving rifle chambers of its era).
Most high-powered guns have relatively small bullets moving at high speeds. This is because while bullet energy increases in direct proportion to bullet weight, it increases in proportion to the square of bullet velocity. Therefore, a bullet going twice as fast has four times the energy (see physics of firearms). Bullet speeds are now limited by starting bore pressures, which in turn are limited by the strength of materials and the weight of gun people are willing to carry. Larger cartridges have more powder, and usually higher velocities.
Of the hundreds of different designs and developments that have occurred, essentially only two basic cartridge designs remain. All current firearms are either rimfire or centerfire. US military small arms suppliers are still trying to perfect electronic firing, which replaces the conventional firing pin and primer with an electrical ignition system wherein an electrical charge ignites the primer.

FIM-92 Stinger

The FIM-92 Stinger is a personal portable infrared homing surface-to-air missile developed in the United States and entered into service in 1981. Used by the militaries of the U.S. and by 29 other countries, the basic Stinger missile has to-date been responsible for 270 confirmed aircraft kills. It is manufactured by Raytheon Missile Systems and under license by EADS in Germany, with 70,000 missiles produced. It is classified as a Man-Portable Air-Defense System (MANPAD).

Light to carry and relatively easy to operate, the FIM-92 Stinger is a passive surface-to-air missile, shoulder-fired by a single operator, although officially it requires two. The FIM-92B can attack aircraft at a range of up to 15,700 feet (4,800 m) and at altitudes between 600 and 12,500 feet (180 and 3,800 m). The missile can also be fired from the M-1097 Avenger vehicle and the M6 Linebacker, an air defense variant of the M2 Bradley IFV. The missile is also capable of being deployed from HMMWV Stinger rack, and can be used by airborne paratroopers. A helicopter launched version exists called the ATAS or Air-to-Air Stinger.
The missile is 1.52 m long and 70 mm in diameter with 10 cm fins. The missile itself weighs 10.1 kg, while the missile with launcher weighs approximately 15.2 kg (33.5 pounds). The Stinger is launched by a small ejection motor that pushes it a safe distance from the operator before engaging the main solid-fuel two-stage motor which accelerates it to a maximum speed of Mach 2.2 (750 m/s). The warhead is a 3 kg penetrating hit-to-kill warhead type with an impact fuze and a self-destruct timer.
In order to fire the missile, a BCU (Battery Coolant Unit) must be inserted into the handguard. This shoots a stream of argon gas into the system, as well as a chemical energy charge that enables the acquisition indicators and missile to get power. The batteries are somewhat sensitive to abuse, and only hold so much gas in them. Over time, and without proper maintenance, they are known to become unserviceable. The IFF antenna receives its power from a rechargeable battery. Guidance to the target is initially through proportional navigation and is then switched to another mode that directs the missile towards the target airframe instead of its exhaust plume.
There are three main variants in use; the Stinger basic, STINGER-Passive Optical Seeker Technique (POST), and STINGER-Reprogrammable Microprocessor (RMP).
The Stinger-RMP is so-called because of its ability to load a new set of software via a ROM inserted in the gripstock at the depot. If this download to the missile fails during power-up, basic functionality runs off the on-board ROM. The four-processor RMP has 4K of RAM for each processor; since the downloaded code runs from RAM, there isn't much space to spare, particularly for the processors dedicated to seeker input processing and target analysis. The RMP has a dual-detector seeker: IR and UV. This allows it to distinguish targets from countermeasures much better than the Redeye, which was IR-only.

Carl Gustav recoilless rifle

The Carl Gustav (also Carl-Gustaf and M2CG) is the common name for the 84 mm man-portable multi-role recoilless rifle produced by Saab Bofors Dynamics (formerly Bofors Anti-Armour AB) in Sweden. The first prototype of the Carl Gustav was produced in 1946, and while similar weapons of the era have generally disappeared, the Carl Gustav remains in widespread use today. British troops refer to it as the Charlie G, while Canadian troops often refer to it as the 84 or Carl G. In US service it is officially known as the RAWS or Ranger Antitank Weapons System, but often called the Gustav or simply the goose by US soldiers. In Australia it is irreverently known as Charlie Gutsache (guts ache, slang for stomach pain). In its country of origin it is officially named Grg m/48 (Granatgevär or grenade rifle, model 48) but is sometimes nicknamed Stuprör (drainpipe) due to the fact that the weapon mainly consists of a long tube.

The Carl Gustav was developed by Hugo Abramson and Harald Jentzen at the Royal Swedish Arms Administration (KAFT) and produced at Carl Gustafs Stads Gevärsfaktori from where it derives its name. The weapon was first introduced into Swedish service in 1948 as the 8,4 cm Granatgevär m/48 (Grg m/48), filling the same anti-tank role as the US Army Bazooka, British PIAT and German Panzerschreck. Unlike these weapons, however, the Carl Gustav used a rifled barrel for spin-stabilizing its rounds, as opposed to fins as used by the other systems.
The use of the recoilless firing system allowed the Carl Gustav to use ammunition containing considerably more propellant, firing its rounds at 290 m/s, as opposed to about 105 m/s for the Panzerschreck and Bazooka and about 135 m/s for the PIAT. The result was superior accuracy at longer ranges. The Carl Gustav can be used to attack larger stationary targets at up to 700 m, but the relatively slow speed of the projectile restricts attacks on moving targets to a range of 400 m or less.
The Carl Gustav was soon being sold around the world, and became one of the primary squad-level anti-tank weapons for many Western European armies. An improved version (M2) was introduced in 1964 and quickly replaced the original version. The current M3 version was introduced in 1991, using a thin steel liner containing the rifling, strengthened by a carbon fiber outer sleeve. External steel parts were replaced with aluminum alloys or plastics, reducing the empty weapon weight considerably from 14.2 kg to 8.5 kg.
In recent years the weapon has found new life in a variety of roles. The British Special Air Service, US Special Forces and United States Army Rangers use M3s in the bunker-busting and anti-vehicle roles, while the German Bundeswehr maintains small numbers of M2s for battlefield illumination. Many armies continue to use it as a viable anti-armor weapon, especially against 1950s and 1960s-era tanks and other armored vehicles, which are still in use worldwide.
The Carl Gustav was used against Taliban defensive fortifications by soldiers of the Princess Patricia’s Canadian Light Infantry in operations in Afghanistan. They developed a new system for firing at night, which involved a night-scope equipped spotter firing tracer ammunitions at the target, and the Carl Gustav gunner then aiming at the spot where the tracer rounds hit.

Shoulder-launched missile weapon

A shoulder-launched missile weapon is a weapon that fires a projectile at a target, yet is small enough to be carried by a single person, and fired while held on one's shoulder. "Missile" is used here in the original broad sense: today the word has a strong connotation with the concept of a guided rocket. There are two kinds of shoulder launched weapons. The first is the recoilless gun, which is essentially an open tube. When fired the reaction gases (with a momentum equal to the projectile) expelled out of the back of the weapon compensate the force exerted on the projectile. The other type uses rocket propelled projectiles; these typically also use a small recoilless charge to get the projectile out of the barrel and to a distance where the operator will not be hurt by the rocket's backblast; when the rocket ignites at a safe distance, it further accelerates the projectile or at least keeps it from decelerating in its trajectory. The smallest shoulder-launched rocket weapons are rocket-propelled grenades (RPG). There are also larger "dumb" shoulder-launched missiles, used in a similar way to an RPG, but with far greater destructive power. A number of specialised "smart" missiles are available in shoulder-launched forms, including (anti-tank guided missile) and man-portable air-defense systems (MANPADs), surface-to-air missiles used as anti-aircraft, typically using infrared homing and used to target helicopters and other low-flying aircraft.

Machine gun

A machine gun is a fully automatic mounted or portable firearm, usually designed to fire rifle cartridges in quick succession from an ammunition belt or large-capacity magazine, typically at a rate of several hundred rounds per minute. The first machine gun was the Maxim Gun, invented by Sir Hiram Maxim in 1884.
In United States law, machine gun is a term of art for any fully-automatic firearm, and also for any component or part that will modify an existing firearm into a fully-automatic firearm.

History:

The Chinese had much success with creating a repeating crossbow; the most common model, the Zhuge Nu, better known in the West as the Chu-ko-nu, is typically attributed to 2nd and 3rd century strategist Zhuge Liang, who developed it for the Kingdom of Shu during the Three Kingdoms period. However, a buried library in the ancient state of Chu indicates that some sort of repeating crossbow had at the very least been designed in the 3rd century BC. Other multi-shot weapons have a long development, going back to the 1st century in the West, with some claiming there were plans for a multi-shot arrow by Hero of Alexandria. Leonardo Da Vinci devised plans for one in the 15th century.
Some of the earliest firearms and attempts at higher rates of fire and some machine-gun-like traits existed as early as the 16th century, when Fathullah Shirazi (c. 1582), a Persian-Indian engineer and polymath who worked for Akbar the Great in the Mughal Empire, invented a multi-barrel gun, which had multiple gun barrels that fired hand cannons loaded with gunpowder. He also invented a primitive autocannon.
However, it would not be until the mid-19th century that successful machine-gun designs came into existence. The key characteristic of modern machine guns, their relatively high rate of fire and more importantly machine (automatic) loading, came with the Model 1862 Gatling gun, which was adopted by the United States Navy. These weapons were still powered by hand; however, this changed with Hiram Maxim's idea of harnessing recoil energy to power reloading in his Maxim machine gun. Dr. Gatling also experimented with electric-motor-powered models; this externally powered machine reloading has seen use in modern weapons as well. The Vandenburg and Miltrailleuse volley (organ) gun concepts have been revived partially in the early 21st century in the form of electronically controlled, multibarreled volley guns. It is important to note that what exactly constitutes a machine gun, and whether volley guns are a type of machine gun, and to what extent some earlier types of devices are considered to be like machine guns, is a matter of debate in many cases and can vary depending which language and exact definition is used.
Future:

Conventional machine-gun development has been slowed by the fact that existing machine-gun designs are adequate for most purposes, although significant developments are taking place with regard to antiarmor and antimissile weapons.
Electronically controlled machine guns with ultrahigh rates of fire, like Metal Storm's weapons may see use in some applications, although current small-caliber weapons of this type have found little use: they are too light for anti-vehicle use, but too heavy (especially with the need to carry a tactically useful amount of ammunition) for individual soldiers. The trend towards higher reliability and lower mass for a given power will likely continue. Another example is the six barreled, 4000 round per minute, XM214 minigun "six pack" developed by General Electric. It has a complex power train and weighs 85 pounds, factors which may, in some circumstances, mitigate against its deployment.

Human interface:

The most common interface on machine guns is a pistol grip and trigger. On earlier manual machine guns, the most common type was a hand crank. On externally powered machine guns, such as miniguns, an electronic button or trigger on a joystick is commonly used. Light machine guns often have a butt stock attached, while vehicle and tripod mounted machine guns usually have spade grips. In the late 20th century, scopes and other complex optics became more common as opposed to the more basic iron sights.
Loading systems in early manual machine guns were often from a hopper of loose (un-linked) cartridges. Manual-operated volley guns usually had to be reloaded manually all at once (each barrel reloaded by hand). With hoppers, the rounds could often be added while the weapon was firing. This gradually changed to belt-fed types. Belts were either held in the open by the person, or in a bag or box. Some modern vehicle machine guns used linkless feed systems however.

Closeup of M2 - This machine gun is part complex armament subsystem; it is aimed and fired from the aircraft rather than directly
Modern machine guns are usually mounted in one of four ways. The first is a bipod - often these are integrated with the weapon. This is common on light machine guns and also medium machine guns. Another major way is with a larger tripod, where the person holding it does not form a 'leg' of support. Medium and heavy machine guns usually use tripods. On ships and aircraft machine guns are usually mounted on a pintle mount - basically a steel post that is connected to the frame. Tripod and pintle mounts are usually used with spade grips. The last major mounting type is one that is disconnected from humans, as part of an armament system, such as a tank coaxial or part of aircraft's armament. These are usually electrically-fired and have complex sighting systems. (For examples see US Helicopter Armament Subsystems). Also there is a Qaud-pod style machine gun.

Al-Khalid tank

The Al-Khalid is a modern main battle tank developed and manufactured by Pakistan for the Pakistan Army. Operated by a crew of three and armed with a 125 mm smooth-bore tank gun that is reloaded automatically, Al-Khalid uses a modern fire-control system integrated with night-fighting equipment to accurately fire many types of anti-tank rounds as well as guided anti-tank missiles. Al-Khalid is named after the legendary Muslim general Khalid ibn al-Walid.
An evolution of Chinese and Soviet tanks, the Al-Khalid is considerably smaller and lighter than most Western main battle tanks. The design is based on the Chinese Type 90-II, which combined technologies from several Soviet/western tanks and is ultimately a descendant of the widely-produced Soviet T-54. The Al-Khalid is unusual in that it is was designed to be adaptable for manufacture, so that it can be easily integrated with a variety of foreign engines and transmissions. The current production variant of Al-Khalid utilises a diesel engine supplied by the KMDB design bureau of Ukraine.
The first production models entered service with the Pakistan Army in 2001 and there are plans to induct approximately 600 in total.

Development history:

In the 1970s, the leadership of China's People's Liberation Army was concerned about the Soviet threat and requested an improved main battle tank (MBT) to replace the old, obsolete Type 59. The existing Chinese tanks were direct descendants of the Soviet T-54A and had were out-classed by more advanced Soviet models like the T-62 and T-64. Norinco and the Inner Mongolia First Machine Group Corporation were tasked to develop a series of new tanks.
After examining samples of T-72 tanks delivered by Iran in the late 1980s (captured from the Iraqi Army), the Chinese military realized contemporary Chinese tanks were still vulnerable. Design features of the T-72 and some western tanks were used to develop a second generation of Chinese tanks, eventually incorporating a redesigned hull and suspension, a new welded turret and 125 mm autoloaded tank gun. The Type 80 and Type 85 tanks led to the Type 90. The Type 90 was rejected for Chinese service in favour of other designs, but it influenced further development which would lead to China's third-generation Type 98 and Type 99 tanks.
The Type 90 is an evolutionary design: the Type 90-II version shares 10% of its components with the Type 59, 15% with Type 69, 20% with Type 85/88C, and is built with 55% new components. This model was put up for sale on the international market.
A development deal was signed with Pakistan in January 1990. Initial Chinese-built prototypes were tested in Pakistan in August 1991. Pakistan spent more than US$20 million over the next ten years on the co-development of a model suitable for their needs and on creating a capability to manufacture it locally. Lt Gen Hamid Javed as Director General of Heavy Industries Taxila (HIT) and Brigadier (now Major General) Mohammad Asaad supervised the project. The design team modified the tank to accept a foreign-built power pack (engine). A number of different prototypes were evaluated.
An early version was armed with a Chinese gun and fire-control system, but had a German-designed MTU-396 diesel engine which was built under licence in China. Another version was equipped with a more advanced western digital fire-control system and powered by a Perkins 1,200 hp (890 kW) Condor diesel engine (as in the British Challenger) and SESM ESM500 automatic transmission (as in the French Leclerc). This version was considered too expensive and under-performing in the extreme heat of southern Pakistan. Finally, a version was tested with the compact Ukrainian 6TD-2 1,200 hp diesel engine (Ukraine also supplied Pakistan with T-80UD tanks, powered by a similar engine). This configuration was chosen for the production version of the tank and came to be known as Al-Khalid.
Yet another version—employing more western technology—had been envisaged as an export product for Pakistan. The prototype had a 1,200 hp (890 kW) German MTU-871/TCM AVDS-1790 diesel engine and an LSG-3000 transmission. But this concept was abandoned due to the arms embargo imposed on Pakistan after the 1998 Pakistani nuclear tests.
The final tank design resulting from a decade of co-operative development was designated Type 90-IIM. Chinese company Norinco showed the new Type 90-IIM during the March 2001 Abu Dhabi Defense Expo, under the export name MBT 2000.
The version powered by the Ukrainian power plant, intended for domestic production in Pakistan, was named Al-Khalid after the prominent companion and general of the Prophet Muhammad named Khalid ibn al-Walid.

Production:

During the development period, Heavy Industries Taxila gained experience building the Chinese Type 85-IIAP and prepared to begin production of the Al-Khalid tank in 1999. A pilot batch of fifteen tanks was inducted into the 31st Cavalry Regiment of Pakistan’s Armoured Corps on 20 July 2001. Pakistan signed a contract with Ukraine's Malyshev Factory in May 2002 for the delivery of 315 6TD-2 engines over three years. An additional batch of Al-Khalid tanks was delivered on 23 September 2004.
Pakistan plans to build a total of 600 Al-Khalid tanks for its armed forces.

JF-17 Thunder

The PAC JF-17 Thunder, also known in China as the Chengdu FC-1 Fierce Dragon (Chinese: 枭龙; pinyin: Xiāo Lóng), is a light-weight multi-role combat aircraft jointly developed by Chengdu Aircraft Corporation of China and Pakistan Aeronautical Complex of Pakistan. The "JF" and "FC" designations stand for "Joint Fighter" and "Fighter China" respectively.
The first two aircraft were delivered to the Pakistan Air Force on 12 March 2007. The JF-17/FC-1 is designed to be a cost-effective fighter which can meet the tactical and strategic needs of air forces of developing countries. On 22 January 2008, Pakistan started limited serial production of the aircraft at the Pakistan Aeronautical Complex, Kamra. Full-fledged production of JF-17 is expected to start from 2009 after completing testing and avionics evaluation.

Development:

The JF-17 is being built by China's Chengdu Aircraft Industry Corporation (CAC) and Pakistan's Pakistan Aeronautical Complex. The project is expected to cost around US$500 million, divided equally between China and Pakistan. The project is supported by China National Aero-Technology Import & Export Corporation for the Chinese side. Each individual aircraft is expected to have a fly-away cost of around US$8-15 million. Initial development of JF-17 is believed to have been completed in a period of four years, although later improvements to the aircraft design did take up more time. Pakistan has announced that it has 150 aircraft on order, but this may well go up to 275. The JF-17 will replace Pakistan's MiG-21-derived Chengdu F-7, Nanchang A-5 and Dassault Mirage III/Mirage V aircraft currently in service. Azerbaijan and Zimbabwe have already placed orders and eight other countries have expressed interest in purchasing the JF-17 at a recent military exhibition in Pakistan, according to an official.

Test flights:

The first prototype was rolled out on 31 May 2003, conducted its first taxi trials on 1 July and made its first flight on 25 August of the same year. The third prototype, PT-03, made its first flight in April 2004. It is believed that at some point during these initial test flights, the name Super-7 was replaced by the Chinese designation FC-1 (Fighter China-1) and the Pakistani designation JF-17 (Joint Fighter-17).
The PT-04 prototype of JF-17 successfully completed its first operational flight in Chengdu, China, on Wednesday 10 March 2006. On 28 April 2006, PT-04 made its first flight with fully operational avionics. This prototype of JF-17 is configured as a multi-role fighter-bomber, equipped with advanced avionics and capable of carrying multiple air-to-air and air-to-ground weapons. Pakistan received the first consignment of 2 aircraft on 23 March 2007. China was supposed to start official production in June 2007 while Pakistan Aeronautical Complex was planning to start manufacturing the JF-17 in 2008.

Self-protection systems:

JF-17 is fitted with a radar warning receiver (RWR) that gives data to the pilot on direction and proximity of enemy radars, as well as an onboard electronic counter-measures (ECM) suite that interferes with these radars to help stop them targeting the aircraft. These systems can be enhanced by the addition of externally-mounted avionics pods:
BM/KG300G self protection jamming (ECM) pod
KZ900 electronic reconnaissance (SIGINT) pod
They also allow the aircraft to take on the roles of aerial reconnaissance and suppression (or destruction) of enemy air defence (SEAD) when armed with the appropriate weaponry.
A missile approach warning (MAW) system uses several optical sensors mounted on the airframe that detect the rocket motors of missiles. Data collected by the MAW system, such as direction of inbound missiles and the time to impact (TTI), is shown on the cockpit displays and HUD to warn the pilot.A countermeasure dispensing system releases decoy flares and chaff to help the aircraft evade enemy missiles and radars trying to track/destroy the aircraft.

Radar:

It has been disclosed by PAF Air Chief Marshal Tanvir Mahmood Ahmed that Pakistan's JF-17s are equipped with the KLJ-7 radar. This is a pulse doppler fire-control radar developed by China's Nanjing Research Institute of Electronic Technology (NRIET). Its multiple modes mean that it can engage targets in the air, on the ground or out at sea. Using the track-while-scan (TWS) mode, enemy aircraft can be engaged at beyond visual range (BVR) while the radar continues scanning for new threats. Close-in aerial combat and ground surveillance modes are also available.
This radar can reportedly manage up to 40 targets, monitor up to 10 of them in track-while-scan (TWS) mode and simultaneously fire on two BVR targets. The detection range for targets with a radar-cross section of up to 3 m2 is stated to be 120 km, or 50 km in look-down mode, while surface sea targets can be detected at up to 135 km. Target data is displayed on the multi-function display screens in the cockpit.
During the early prototype stage a number of radar systems were tested for both production and possible export versions. A number of other radars have also been considered for export versions of the aircraft, one of these is the Italian FIAR Grifo S7, which was tailored to meet the PAF's initial requirements of the Super-7.

Heckler & Koch G3

The G3 is a 7.62 mm automatic rifle developed in the 1950s by the German armament manufacturer Heckler & Koch GmbH (H&K) in collaboration with the Spanish state-owned design and development agency CETME (Centro de Estudios Técnicos de Materiales Especiales).

Development:

The origin of this rifle can be traced back to the final years of World War II when engineers at the German Mauser factory designed the 7.92 mm StG45 assault rifle, first with the Gerät 06 ("device 06") using a roller-delayed blowback mechanism originally adapted from the roller-locked recoil operating system of the MG42 machine gun but with a fixed barrel and gas system. It was realized that with careful attention to the mechanical ratios, the gas system could be omitted. The resultant weapon, the Gerät 06(H) was assigned the designation StG45(M) but was not produced beyond prototype stage.
The German technicians involved in developing the Sturmgewehr 45 continued their research in France at CEAM. The StG45 mechanism was modified by Ludwig Vorgrimler and Theodor Löffler at the Mulhouse facility between 1946 and 1949. Three versions were made, chambered in .30 Carbine, 7.92x33mm Kurz as well as the 7.65x35mm cartridge developed by Cartoucherie de Valence and adopted in 1948. A 7.5x38mm cartridge using a partial aluminium bullet was abandoned in 1947. Löffler's design, designated the Carabine Mitrailleuse Modèle 1950, was retained for trials among 12 different prototypes designed by CEAM, MAC, and MAS. Engaged in the Indochina War and being the second NATO contributor, France canceled the adoption of these new weapons for financial reasons.
In 1950, Vorgrimler moved to Spain where he created the LV-50 rifle chambered in the intermediate 7.92x33mm Kurz cartridge and later, the proprietary 7.92x40mm CETME M53 round. At this point, the rifle was renamed the Modelo 2. The Modelo 2 attracted a lot of attention from the West German Border Guards (Bundesgrenzschutz), which sought a new service rifle. Not willing to accept a cartridge outside of the NATO specification, the Germans asked CETME to develop a 7.62 mm version of the rifle. The resulting CETME rifle Model A was chambered for the 7.62x51mm CETME cartridge which has identical chamber dimensions but a reduced-power load compared to the 7.62x51mm NATO round. Further development of the rifle with input from HK produced the CETME Model B which received several modifications including the ability to fire from a closed bolt in both semi-automatic and automatic firing modes, a new perforated sheet-metal handguard (the folding bipod had been the foregrip in previous models), improved ergonomics and a slightly longer barrel with a rifle grenade launcher guide. In 1958, this rifle was introduced into service with the Spanish Army as the Modelo 58, firing the 7.62x51mm CETME round.
In 1956, the Bundesgrenzschutz canceled its planned procurement of the CETME rifles, adopting the FN FAL (G1) instead. However, the newly formed West German Army (Bundeswehr) now displayed interest and soon purchased a number of CETME rifles (7.62x51mm NATO chambering) for further testing. The CETME, known as the Automatisches Gewehr G3, competed successfully against the SIG SG 510 (G2) and AR-10 (G4) to replace the previously favored G1 rifle. In January 1959, the Bundeswehr officially accepted the CETME rifle. The West German government wanted the G3 rifle to be produced under license in Germany; purchase of the G1 had previously fallen through over FN's refusal to grant such a license. In the case of the G3, the Dutch firm Nederlandse Wapen en Munitiefabrik (NWM) held production and sales rights to the CETME design outside of Spain. To acquire production rights, the West German government offered NWM contracts to supply the Luftwaffe with 20 mm ammunition. Production of the G3 was then assigned to Rheinmetall and HK. The latter company already had ties to CETME, and had worked to further optimize the CETME rifle for use with the full-power 7.62x51mm NATO cartridge (as opposed to the downloaded CETME variant). In 1969, Rheinmetall gave up production rights to the G3 in exchange for HK's promise not to bid on MG3 production. Later in 1977, the West German government ceded ownership of G3 production and sales rights exclusively to HK.
Initial production G3 rifles differed substantially from more recent models; early rifles featured closed-type mechanical flip iron sights (with two settings), a lightweight folding bipod, stamped steel handguard, wooden buttstock (in fixed stock models) and a telescopic metal stock (in folding stock models). The weapon was modernized during its service life (among other minor modifications it received new sights, a different flash hider, a plastic foregrip and stock), resulting in the current production variants, the G3A3 (with a fixed synthetic stock) and the G3A4 (telescoping metal stock). The rifle proved successful in the export market, being adopted by the armed forces of over 40 countries. The G3 was and in some cases continues to be produced under license in: France (MAS), Greece (Hellenic Arms Industry), Iran (Defense Industries Organization), Mexico, Myanmar, Norway (Kongsberg Våpenfabrikk), Pakistan (Pakistan Ordnance Factories), Portugal (FBP), Saudi Arabia, Sweden (FFV), Thailand, Turkey (MKEK) and the United Kingdom (Royal Ordnance).

The Saga of Seven

I'm sure that in 1892 when Peter Paul Mauser was putting the finishing touches on a 7mm cartridge he had just designed, little did he know he was launching what would prove to be the most popular game caliber in the history of smokeless powder.

One 7mm that enjoyed a certain degree of popularity in the '50s was the 7x61 Sharpe & Hart (left) and in the 1960s, the .284 Win.
Here in the states the 7mm bore will in all probability remain a distant second in popularity to the .30 caliber, but when you consider the advantages the .30 has had, it's pretty impressive how popular the 7mm has become in such a relatively short span of time. After all, the .30 was the official caliber of the U.S. military from 1892 to 1967, first in the form of the .30-40 Krag, followed by the .30-06 and then the .308 Win. (7.62 NATO). Then there's the little matter of there being some 10 million Winchester Model 94 and Marlin lever-action rifles chambered in .30 WCF. It's no wonder, then, that no matter how you track it--through sales of loading dies, component bullets, loaded ammunition or unprimed brass--.30 will always come up number one simply because there are so many of them out there. New-gun sales figures, however, are something else again, for the 7mm competes quite successfully with the .30 in that category.
Anyway, the 7mm as a smokeless-powder caliber was launched when Spain adopted the 7mm Mauser as its martial cartridge in 1893, first in a limited number of Mauser's Model of 1892, then in serious quantities in the Model '93. The cartridge is known by at least four names: Spanish Mauser, 7mm Mauser, 7x57 and in England as the .275 Rigby. It was eventually adopted by the armies of Mexico, Brazil, Chile, Uruguay, Colombia, Venezuela, Costa Rica, Serbia, China, Persia, Transvaal and the Orange Free State.

The first American company to chamber for the 7mm Mauser was Remington in its Model 1897 Rolling Block Military Carbine, the entire production of which went to the Mexican government. The following year, though, the chambering was offered in the No. 5 Sporting & Target Rifle version of the Rolling Block, along with the .30-30 Win. and .30-40 Krag. That same year the 7mm chambering was also added to the five-shot Remington-Lee bolt action rifle. In either case, relatively few 7mm Mauser rifles found themselves in the hands of America's hunters and shooters.
The story here stayed pretty much the same through the 1920s, '30s and '40s--Remington only offered the 7mm in its '17 Enfield-based Model 30 bolt-action rifle and Winchester in its Model 54 (and later in the Model 70). All together, though, it was a mere drop in the bucket; few other than handloading rifle cranks were even aware of the 7mm's existence.

Prior to the arrival of the .280 Rem in 1957, these three were the major players in the 7mm game (left to right): 7mm Mauser (7x57), 7x61 Sharpe & Hart and 7mm Weatherby Magnum.
The only other 7mm cartridges that had any presence whatsoever on these shores were the 7x64 Brenneke and the 7x61 Sharpe & Hart, for which Norma of Sweden was the main source of ammunition--also, the 7mm Weatherby Magnum, which goes back to the mid-'40s. But again, we're talking a tiny percentage of avante garde hunters handloading for custom-built rifles. As a caliber, the 7mm was still wallowing in obscurity as late as the 1950s.
That all started to change, however, in 1957 when Remington introduced its .280, the first commercial 7mm (.284) cartridge from a major American arms company. The .280's sole raison d'etre was to compete with the phenomenally popular .270 Win. With the 20/20 hindsight that time bestows, it can be said that Remington made a mistake by developing the .280 for use in the semiauto Model 740 because it had to be loaded to pressures levels below those used for the .270 Win., which was designed strictly for bolt guns. Once that decision had been made and there were rifles and ammo in the hands of consumers, there was no turning back.

Operating mechanisms

Single-action (SA) handguns have a trigger whose sole function is to drop a pre-cocked hammer to discharge a cartridge. For revolvers, the popular Colt Peacemaker of Old West fame is typically thought of. Its hammer must be manually cocked for each shot. For auto-loading pistols the Colt 1911 or Browning Hi-Power are typical examples. They must be cocked for the first shot, but subsequent shots are cocked automatically due to the racking of the slide. These types of guns typically have a very light and crisp trigger pull, making for more accurate target shooting.

Jericho 941 F (DA), 9 mm with magazine removed
Traditional double-action (DA) handguns have a mechanism that can be either pre-cocked, like the above single-action gun, or can be fired with the gun uncocked. In this case, the gun has an additional mechanism added to the trigger that will cock the gun (and rotate the cylinder in the case of revolvers) as the trigger is pulled. Once the trigger is pulled far enough, the hammer is released and the gun fired. For autoloading pistols the self-loading mechanism will also re-cock the hammer after the first shot is fired so that subsequent shots are fired single-action. For revolvers, each shot is fired with the hammer initially uncocked unless the shooter manually cocked the gun. Popular auto pistols in this category include the Walther P38 and Beretta 92. These guns typically have a longer, heavier trigger pull for the first shot then light, crisp pulls for subsequent shots. Popular revolvers include the Ruger Redhawk and Smith & Wesson Model 29. These have comparatively long, heavy trigger pulls for all shots unless the revolver is manually cocked.
Double-action only (DAO) handguns do not have the ability to be cocked and is usually evidenced by a lack of either the hammer spur or the entire hammer. A typical autopistol in this category is the Ruger KP93DAO and Taurus Millennium, and a typical revolver is the Smith & Wesson Centennial or the Enfield No 2 Mk I*. All pistols in this category have a long, heavy trigger pull for all shots.
Pre-set triggers are only on autoloading pistols. In this case the pistol mechanism is always partially cocked while being carried and during firing. The partially-cocked firing pin or striker is not cocked enough to cause an accidental release to discharge a cartridge, adding to the safeness of the design, but is cocked enough to remove much of the trigger pull and weight of a purely double-action pistol. These types of pistols do not have external hammers and do not generally have a decock function. Common pistols in the category are the Springfield Armory XD and the various forms of the extremely popular Glock. The trigger pull of these guns is between double-action and single-action pistols. Pre-set triggers may or may not have a second-strike feature on a dud cartridge.
Some automatic pistol models such as the HK USP Universal Self-loading Pistol come in a variety of mechanism types and can be easily changed by a gunsmith for both left- and right-handed shooters and for different operating mechanism and safety features.
Glock introduced a new "Safe Action" mechanism that is neither a single nor double action. The action is not cocked, rather the firing pin is pulled back by the trigger, resulting in the first and subsequent trigger pulls all being the same and the weapon also being safer.

Semi-automatic pistols

The next development in handgun history after a practical revolver was the development of the semi-automatic pistol, which uses the energy of one shot to reload the chamber for the next. Typically recoil energy from a fired round is mechanically harnessed, however larger calibers may also be gas operated (e.g. Desert Eagle). After a round is fired, the pistol will cycle, ejecting the spent casing and chambering a new round from the magazine, allowing another shot to take place immediately.
Some terms that have been, or still are, used as synonyms for "semi-automatic pistol" are automatic pistol, autopistol, autoloader, self-loading pistol and selfloader.

Revolvers

With the development of the revolver in the 19th century, gunsmiths had finally achieved the goal of a practical capability for delivering multiple loads to one handgun barrel in quick succession. Revolvers feed ammunition via the rotation of a cartridge-filled cylinder, in which each cartridge is contained in its own ignition chamber, and is sequentially brought into alignment with the weapon's barrel by a mechanism linked to the weapon's trigger (double-action) or its hammer (single-action). These nominally cylindrical chambers, usually numbering between five and eight depending on the size of the revolver and the size of the cartridge being fired, are bored through the cylinder so that their axes are parallel to the cylinder's axis of rotation; thus, as the cylinder rotates, the chambers revolve about the cylinder's axis.
There is a hybrid form of the revolver, known as the automatic revolver, which combines the revolving chamber concept of the conventional revolver with the recoil-harnessing, self-cycling ability of the semi-automatic pistol. Weapons of this type are rare, as the technology was quickly rendered obsolete by a combination of the double-action revolver and the semi-automatic pistol.

Handgun

A handgun is a firearm designed to be held and operated by one hand, with the other hand optionally supporting the shooting hand. This characteristic differentiates handguns as a general class of firearms from their larger counterparts: long guns such as rifles and shotguns (which are held in both hands and usually braced against the shoulder), mounted weapons such as machine guns and autocannons, and larger weapons such as artillery.
Some handgun subtypes include single-shot pistols, revolvers, semi-automatic pistols, pepperboxes, and machine pistols.

Multiple senses of the word "pistol":

The word "pistol" is often synonymous with the word "handgun". Some handgun experts make a technical distinction that views pistols as a subset of handguns. In American usage, the term "pistol" refers to a handgun whose chamber is integral with the barrel, making pistols distinct from the other main type of handgun, the revolver, which has a revolving cylinder containing multiple chambers. However, Commonwealth usage makes no distinction at a technical level—"pistol" may refer to revolvers, semi-automatics, or muzzle-loading/cap-&-ball handguns. For example, the official designation of the Webley Mk VI was "Pistol, Revolver, Webley No. 1 Mk VI", and the designation "Pistol No. 2 Mk I" was used to refer to both the Enfield Revolver and the later Browning Hi-Power semi-automatic.
The first pistols were made as early as the 15th century, however the creator is unknown. By the 18th century, the term came to be used often to refer to handheld firearms. Practical revolver designs appeared in the 19th century, and it was in that century that the (sometimes-observed) technical differentiation in usage of the words "pistol" and "revolver" developed.

Pump-action

A pump-action rifle or shotgun is one in which the handgrip can be pumped back and forth in order to eject and chamber a round of ammunition. It is much faster than a bolt-action and somewhat faster than a lever-action, as it does not require the trigger hand to be removed from the trigger whilst reloading. When used in rifles, this action is also commonly called a slide action.
The term pump-action can also be applied to various airsoft guns and air guns, which use a similar mechanism to both load a pellet and compress a spring piston for power, or pneumatic guns where a pump is used to compress the air used for power. See the airgun article for information on how spring piston and pneumatic airguns work.

Advantages:

The speed of cycling of a pump-action is quite fast, often less than that of some semi-automatic designs. The manual operation gives a pump-action the ability to cycle rounds of widely varying power that a gas or recoil operated firearm would fail to cycle, such as most less than lethal rounds. The simplicity of the pump-action relative to a semi-automatic design also leads to improved durability and lower cost. It has also been noticed that the time taken to work the action allows the operator to identify and aim on a new target, avoiding a "spray and pray" usage. Also, the ratcheting sound made by a pump-action weapon being pumped is distinct enough to some times cause would-be attackers and intruders to flee, even if they can not see the weapon or user, allowing the weapon to perform its ultimate self-defense purpose without even being fired.

Disadvantages:

Like a lever-action rifle, a clip cannot effectively be utilized in pump-action firearms. This makes for slow reloading, as the cartridges have to be inserted individually into the firearm.

Layout:

A pump-action firearm is typically fed from a tubular magazine underneath the barrel, which also serves as a guide to the movable forend, although some, notably the Remington 760 rifle and its successors, use detachable box magazines. The rounds are fed in one by one through a port in the receiver, where they are pushed forward. A latch at the rear of the magazine holds the rounds in place in the magazine until they are needed. 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. Pump shotguns with detachable box magazines or even drums exist, and may or may not allow the magazine to be inserted without stripping the top round.

Operating cycle:

Nearly all pump-actions use a back-and-forward motion of the forend to cycle the action. The forend is connected to the bolt by one or two bars; two bars is considered better because it provides symmetric forces on the bolt and pump and reduces the chances of binding. The motion of the bolt back and forth in a tubular magazine model will also operate the elevator, which lifts the shells from the level of the magazine to the level of the barrel.
After firing a round, the bolt is unlocked and the forend is free to move. The shooter pulls back on the forend to begin the operating cycle. The bolt unlocks and begins to move to the rear, which extracts and ejects the empty shell from the chamber, cocks the hammer, and begins to load the new shell. In a tubular magazine design, as the bolt moves rearwards, a single shell is released from the magazine, and is pushed backwards to come to rest on the elevator.
As the forend reaches the rear and begins to move forward, the elevator lifts up the shell, lining it up with the barrel. As the bolt moves forward, the round slides into the chamber, and the final portion of the forend's travel locks the bolt into position. A pull of the trigger will fire the next round, where the cycle begins again.
Most pump-action firearms do not have any positive indication that they are out of ammunition, so it is possible to complete a cycle and have an empty chamber. The risk of running out of ammunition unexpectedly can be minimized in a tubular magazine firearm by topping off the magazine by loading new rounds to replace the rounds that have just been fired. This is especially important when hunting, as many locations have legal limits on the magazine capacity: for example, three rounds for shotguns and five rounds for rifles.

AK-47

The AK-47 (contraction of Russian: Автомат Калашникова образца 1947 года; Avtomat Kalashnikova obraztsa 1947 goda; "Kalashnikov's automatic rifle model of year 1947") is a 7.62 mm assault rifle developed in the Soviet Union by Mikhail Kalashnikov in two versions: the fixed stock AK-47 and the AKS-47 (S—Skladnoy priklad) variant equipped with an underfolding metal shoulder stock.

Design work on the AK began in 1944. In 1946 the rifle was presented for official military trials, and a year later the fixed stock version was introduced into service with select units of the Red Army (the folding stock model was developed later). The AK-47 was officially accepted by the Soviet Armed Forces in 1949. It was also used by the majority of the member states of the former Warsaw Pact. The AK-47 was also used as a basis for the development of many other types of individual and crew-served firearms.

It was one of the first true assault rifles and, due to its durability, low production cost and ease of use, remains the most widely used assault rifle in the world - so much so that more AK-type rifles have been produced than all other assault rifles combined.

Features:

The main advantages of the Kalashnikov rifle are its simple design, fairly compact size and adaptation to mass production. It is inexpensive to manufacture, and easy to clean and maintain; its ruggedness and reliability are legendary. The AK-47 was initially designed for ease of operation and repair by glove-wearing Soviet soldiers in Arctic conditions. The large gas piston, generous clearances between moving parts, and tapered cartridge case design allow the gun to endure large amounts of foreign matter and fouling without failing to cycle. This reliability comes at the cost of accuracy, as the looser tolerances do not allow for precision and consistency. Reflecting Soviet infantry doctrine of its time, the rifle is meant to be part of massed infantry fire, not long range engagements. The average service life of an AK-47 is 20 to 40 years depending on the conditions to which it has been exposed.

The notched rear tangent iron sight is adjustable, and is calibrated in hundreds of meters. The front sight is a post adjustable for elevation in the field. Windage adjustment is done by the armory before issue. The battle setting places the round within a few centimeters above or below the point of aim out to about 250 meters (275 yd). This "point-blank range" setting allows the shooter to fire the gun at any close target without adjusting the sights. Longer settings are intended for area suppression. These settings mirror the Mosin-Nagant and SKS rifles which the AK-47 replaced. This eased transition and simplified training.

The prototype of the AK-47, the AK-46, had a separate fire selector and safety. These were later combined in the production version to simplify the design. The fire selector acts as a dust cover for the charging handle raceway when placed on safe. This prevents intrusion of dust and other debris into the internal parts. The dust cover on the M16 rifle, in contrast, is not tied to the safety.

The bore and chamber, as well as the gas piston and the interior of the gas cylinder, are generally chromium-plated. This plating dramatically increases the life of these parts by resisting corrosion and wear. This is particularly important, as most military-production ammunition during the 20th century contained Potassium chlorate in the primers. On firing, this was converted to corrosive and hygroscopic Potassium chloride which mandated frequent and thorough cleaning in order to prevent damage. Chrome plating of critical parts is now common on many modern military weapons.