A rifle is a shoulder fired firearm that has rifled grooves in the barrel. These grooves make the bullet spin around an axis which stabilizes it during the flight. This makes the bullet more accurate and improves its range. Initially, rifles were known as "rifled guns". However, the term "rifle" gradually replaced the earlier term in common usage. Rifles are commonly used in warfare, sports shooting and hunting.A rifle bullet is propelled by using an explosive such as nitrocellulose. In the earlier days, black powder was the commonly used propellant. However, due to its disadvantages such as thick smoke and sooth, it was replaced with smokeless powder. Some rifles are also powered by compressed air. These rifles are generally used for pest control and for target practice.There are many misnomers around the terms "gun" and "rifle". In common language, the term gun refers to small weapons. However in actuality, the term "gun" can refer to any firearm--from a handheld revolver to a large sized artillery piece. Similarly, all firearms fired from the shoulder are commonly called "rifles". However, this is not true. Shotguns do not have rifled barrels and so it would be incorrect to call a shotgun a rifle.Traditionally, rifles were capable of firing only a single round at a time. However, modern rifles are capable of firing both in bursts and in fully-automatic mode. In fact, modern rifles overlap with submachine guns in many regards. Many machine guns designed for squad support are modified versions of assault rifles. For example, the Soviet RPK is a modified AK-47 with a heavier barrel and a bipod.The rifle's origin can be traced back to the original smoothbore musket. These muskets lacked range and accuracy. In addition, they were loaded from the muzzle.In the subsequent years, it was discovered that cutting grooves into the barrel of the musket imparts spin to the projectile which stabilizes the bullet and increases the accuracy and range. It was not possible to load a rifle from the muzzle. The bullet would fit tightly into the barrel and because of the grooves, pushing it down the barrel was difficult. In addition, the bullet would also push dirt and soot deposited on the barrel from earlier shots and thus would jam the rifle.Subsequently, a few developments were made to resolve the issue. One approach involved using a smaller ball which would expand upon firing. The second approach involved using a ball wrapped in a greased cloth. However, none of these were satisfactory and eventually breech-loaded rifles became with standard with armies across the globe.The main differences between a machine gun and an assault rifle lie in the weight and ammunition capacity. Machine guns have heavier barrels and feed from a belt. The heavier barrel ensures that the weapon doesn't get overheated and the belt ensures adequate firepower in the field. Assault rifles are designed to be fired by a single soldier. Machine guns may require a crew to operate.

The OICW XM29 is a new rifle design developed with the intention of taking the capabilities of the battle rifle to a new level. OICW stands for “Objective Infantry Combat Rifle”. The rifle was developed by Alliant Techsystems and Heckler & Koch in 1990s.

The XM29 has two gun systems: a 20 mm barrel capable of firing airburst rounds in semi-automatic mode and a 5.56mm assault carbine underneath it. In addition, the weapon also comes equipped with advanced laser optics. With the XM29, it is possible to shoot around corners. By using the laser rangefinder, it is possible to pin the 20 mm airburst round at a specific point. When the ammunition explodes in mid-air, it rains down shrapnel causing injury to enemy personnel hidden behind corners or obstacles.

Various problems were encountered during the design and testing of the OICW. Subsequently, the program was cancelled and split into three related programs. One of the main problems was the bulk and weight of the weapon. In addition, the 20 mm round was not found to be effective enough. The electronic components of the weapon also have their own drawbacks.

The main project was split into three new projects—one aimed at improving the light assault rifle, the other aimed at the 20 mm gun and the third dealing on ways to integrate both. As of today, the first project has been canceled. However, the second project continues and a variant known as the XM25 is being actively developed.

The Heckler & Koch G11 is an experimental bullpup rifle on the 1970s and 80s. The design of the G11 is highly unconventional. It is also notable for its use of case-less 4.7x33mm ammunition. Since it uses case-less ammunition, it doesn't have an ejection mechanism as the all the contents of the chamber are ejected out of the barrel when the ammunition charge is ignited.

The G11’s ammunition consists of a block of propellant and the bullet embedded into it. Since, the weapon doesn’t have an ejection mechanism its reliability is significantly increased. It may be noted that most weapons malfunction because of problems with the ejection system. In addition, the smaller round of the G11 also means that more ammunition can be carried without adding extra weight.

The G11 can fire both in automatic mode and also in a three-burst mode. In the three-burst mode, all the three rounds are ejected simultaneously one after another in a single recoil cycle. This gives the weapon a superb firing rate of 2200 rounds per minute.

The G11 is accurate up to 500 meters. It also comes with an optical scope for better accuracy. Its bullpup design and advanced construction make the weapon very small and light-weight.

One of the main problems encountered during the design and testing of the G11 was the issue of ammunition “cooking-off”. In a normal rifle, the ammunition casing absorbs most of the heat generated by the propellant. Subsequently, as the casing gets ejected the chamber doesn’t heat up and so the next round that enters the chamber doesn’t “cook off” until the igniting pin hits it. However, in the case of the G11, since there is no casing, the chamber heats up causing the next round to cook off as soon as it enters the chamber. The problem of ammunition “cooking off” was solved by created a new type of propellant that had a higher ignition temperature.

Though the G11 proved to be an engineering challenge to its designers, it was nevertheless a successful weapon at least design wise. However, it was not adopted by any mainstream, service due to its high manufacturing costs. Nevertheless, its design easily outshines other conventional rifles.

The FN P90 is a personal defence weapon designed by Fabrique Nationale de Herstal in Belgium. It was designed as a compact weapon for use by vehicle drivers, support personnel, tank crew and counter terrorism squads. It is chambered for proprietary 5.7x28mm ammunition.

Just like the Calico M950, the FN P90 can be classified into several categories of weapons. It is both a carbine and a submachine gun. It has a compact bull-pup design and is constructed from polymers and alloys which make it very light weight.

The P90 has a rather unusual design and also uses newly designed ammunition. The reasoning behind its design is that both submachine guns and handguns cannot provide range and stopping power, especially when used against body armour. The P90 fulfills that drawback with its high range and penetrative power. The 5.6x28mm round developed by FN for use with the P90 has a good range and can penetrate body armour and standard military helmets at ranges of 50 to 100 meters.

The FN P90 can be fired from both right and left sides. It has cocking levers on both the sides that enable the firer to cock the gun from any side. In addition, the selector is located below the trigger. It also uses an innovative feed system. During the loading process, the bullets are held at right angles to the breech and when fed into the chamber they get aligned by means of a ramp.

The P90’s design is very innovative and ergonomic. It can be safely said that the P90 will be the forerunner of a range of personal defence weapons of the future. Its design will definitely inspire gun designs of the near future.

The Calico M950 is a semi-automatic pistol cum carbine type-weapon designed and manufactured by Calico Light Weapons Systems. It is chambered for the .22 LR and the 9mm Parabellum ammunition. It feeds using a round barrel shaped magazine that is mounted from the top. The barrel can hold either 50 or 100 rounds.

The Calico M950 appears like a large handgun but has enough barrel shrouding that allows it to be wielded as a submachine gun. Some variants of the M950 also have a foregrip that allows for more stable firing. It has a long barrel because of which it is fairly accurate up to 60 meters. The pistol can be fired only in semi-automatic mode and offers good firepower.

The M950 is an intermediary weapon. It is too large to be classified as a pistol and at the same time lacks the stock of a carbine or rifle. However, it is very useful in the field (at least in theory). Due to its low weight, it can come very handy during tight situations in the field. At the same time, its impressive firepower can come very handy.

The M950 is an experimental weapon and very few countries have adopted it. Irrespective of whether the M950 and the concept behind it will catch on or not, it can be clearly stated that it is a fascinating experiment and will definitely leave its imprint on gun designs in the future.

The Colt M4 is a carbine version of the M16. It is shorter and lighter than the parent rifle. However, about 80% of the parts of the M4 can be interchanged with the M16. The M4 differs from the M16 only in the butt stock and barrel shroud.

The Colt M4 has been the basis of several variants. One such example is the M4A1. The M4A1 is a fully automatic version while the M4 fires only in selective fire mode.

The M4 and its variants are chambered to fire the 5.56x45mm NATO round and feed using a 30-round box magazine. They can also be fed using other STANAG magazines. With a rate of fire approximating 700-950 rounds per minute, the M4 is accurate up to 360 meters.

The M4 is very popular with Special Forces and security personnel. The M4 is preferred for its heavy-weight stopping power. The rifle is much shorter than the M16 thus making it a better choice for operations requiring quick deployment. However, the M4 has high muzzle-flash which needs a flash suppressor for effective use.

The SA80 L85A1 is a British bullpup configuration rifle developed in the 1980s. The debut of the rifle was not auspicious. It was adopted by the British to replace the earlier SLRs.

Though the design of the SA80 was very good on paper and the rifle proved it to be very effective during the initial tests, problems arose when it was deployed in the field. Some of these problems were quite serious in nature.

The SA80 was prone to serious malfunction when it became dirty. In addition, the rifle’s cocking handle would often break apart during use which would render the rifle completely useless. Another design flaw with the SA80 made the magazine to get accidentally released when the rifle was carried. This was a liability when the weapon had to be brought into action all of a sudden and also may result in live ammunition ending up in enemy hands.

Despite these disadvantages, the SA80 saw wide spread deployment in conflicts where Britain was involved. It was deployed in Northern Ireland, Iraq during the First and Second Gulf Wars, Bosnia, Kosovo, Sierra Leone and Afghanistan.

It was also exported to a few countries—most notably Venezuela. Venezuela acquired these rifles for its Special Forces. However the rifle was found to be lacking in terms and reliability and thus the rifle was dismissed from service subsequently.

The FAMAS is a French bullpup assault rifle designed by Paul Tellie in 1967. The rifle was accepted into service by the French Armed Forces in 1978 and is still in use.

The FAMAS is a very small rifle, even by bullpup standards. However, it is very robustly constructed and is extremely reliable in the field. The rifle is chambered for the 5.56x45mm NATO round and feeds from a 25 or 30-round box magazine box. It is accurate up to a range of 300 meters.

The FAMAS is commonly known as ‘Le Clarion’ which means ‘Bungle’ or ‘Trumpet’ in French after its shape. The body of the rifle is constructed from special alloys which makes it very robust. The furniture of the rifle is made from fibreglass.

The FAMAS rifle was deployed in Chad during Operation Manta. Subsequently, it saw action in Kuwait during the First Gulf War. In all these operations, the FAMAS proved itself to be very reliable and trustworthy.

The Steyr-Mannlicher AUG is an Austrian assault rifle manufactured by Steyr Mannlicher GmbH & Co KG. The rifle was designed in the early 1970s and adopted by the Austrian Armed Forces in 1977. In Austria, the AUG is used by both the military and the police forces.

The AUG is an excellent weapon and is very reliable in the field. Though externally the AUG may appear to be fragile, it is very rigidly constructed and so is very reliable. It is designed for the 5.56x45mm NATO round and uses a clear-plastic magazine holding 30 or 42 rounds as its feed system.

Various parts of the rifle such as the stock are made of fibreglass-reinforced polyamide. This makes the rifle comparatively light-weight. In addition, the rifle also makes use of the bullpup configuration which makes it very short. Because of the bullpup configuration, the rifle is very short yet the barrel is long enough to ensure accuracy over a range of 300 meters.

The AUG serves both as an assault rifle in close-quarter combats and also as a support rifle. It is available in several barrel lengths and a 9mm submachine gun version is also available.

The Aug is employed by a number of countries such as Australia, France, Germany, Ireland, Italy, Morocco, Saudi Arabia, United Kingdom, United States and Uruguay.

The SIG SG 540 is a 5.56mm assault rifle designed by the Swiss arms company SIG in 1970s. It was designed primarily for export to other countries.

SIG is well known for developing extremely good albeit expensive weapons. The SG 540 is one such weapon. The SG 540 doesn’t have any cutting-edge features. However, it is extremely reliable and adaptable to the field situations.

The SIG SG 540 is chambered to utilize the 5.56x45mm NATO round and feeds from a 20 or 30-round magazine. It can also be used to fire grenades without using any additional equipment. The rifle is accurate up to a distance of 800 meters. By adding suitable aiming optics, the SG 540 can also be used as a sniper rifle.

The SG 540 comes with a fixed or a metal foldable stock. In addition, it also comes with a foldable bipod for better control during firing. The stock, grip and hand guard of the rifle are made of hardened polymer to reduce weight. Other metal parts are made of stamped steel which makes the manufacturing process inexpensive.

Variants of the SG 540 include SG 542, SG 543 and SG 550. The SG 542 is chambered for a higher-power round and also has modifications done to the iron sights. The SG 543, on the other hand, is a shortened ‘carbine’ version of the SG 540. The SG 550 is a selective fire weapon built over the SG 540 with several new added features.

The SIG SG 540 is very popular and many countries across the globe are currently using it. Some of the countries include Chile, France, Indonesia, Oman, Paraguay, Portugal and Tago.

INSAS is a family of rifles designed and manufactured in India by the Indian State Ordnance Factory Board, Ishapore. The INSAS assault rifle currently the standard issue rifle of the Indian Army.

Development on the INSAS began in the 1980s when it was felt that earlier FN FAL fielded by the Indian Army was inadequate the meet the requirements in the changing field of warfare. Thus development began on the new arms system. By the year 1997, the INSAS rifle was ready for mass production and the rifle was first presented to the public on the Republic Day Parade in 1998. Currently, 300,000 INSAS rifles are in use with the Indian Armed Forces.

The INSAS combines the design features of the AK-47, the Heckler & Koch G3 and the M16. It combines the AK-47s gas mechanism, the G3 rifle’s changing handle position and the M16’s burst modes and is often considered by many military experts as one of the best rifles currently in use.

The INSAS is chambered for the 5.56x45mm NATO and is accurate up to a distance of 450 meters. It can fire bullets at a round of 650 rounds per minute. The rifle can also be fitted with grenade launchers and bayonets for providing additional support in the field.

Though the INSAS is a top-notch weapon, the initial versions had some operational glitches. It has reliability problems in extremely cold conditions and often jams. In addition, the polymer parts of the rifle are also prone to cracking in cold weathers. Sometimes, it was also observed that the rifle would fire in fully-automatic mode when in three-round mode. However, the recent versions seem to have fixed these problems.

The INSAS rifle has been exported to Nepal in significant numbers. Though proper details are not available, some sources claim that around 100,000 units have been exported to Nepal in view of the recent Maoist insurgency.

The Heckler & Koch G36 is a German assault rifle chambered for the 5.56x45mm NATO round. It was designed by Heckler & Koch in the early 1990s and adopted by the German Armed Forces in 1997. It replaced the older G3 battle rifle from the Army’s inventory.

The H & K G3 was very reliable and many variants were developed based on its design. These variants ranged from full-sized rifles to submachine guns. The G36 is also based on the G3 and uses a similar receiver design. However, it doesn’t use the roller-locking delayed blowback mechanism of the G3 and instead operated on gas. The rifle is designed for use mainly as a light support weapon.

The G36 has been the basis of several variants. For example: The G36K—a carbine version of the G36 and the G36C—a smaller variant designed for use in close-quarter combat. The G36 and its variants are made from a number of high-quality polymers. The receiver housing, stock, magazine well and the carry handle are made of reinforced polyamine carbon fibre.

The G36 can also be fitted with a grenade-launcher for additional utility in the field. With the rifle spare magazines, a maintenance kit, a speed loading kit and a AK-47 style bayonet are issued.

The G36 is currently being used by a number of countries across the world. Some of these include Australia, Belgium, Brazil, France, Germany, Norway, Romania, Sweden, United Kingdom and the United States. The United States Safety and Security Service also employs the H & K G36.

The Valmet M76 is an assault rifle designed in Finland. It was manufactured from 1976 to 1986 and came in two calibres: 7.62x39mm and 5.56x45mm NATO. A semi-automatic version of the M76 was also developed for use by civilians. The M76 is also designated as RK 62 76.

Finland was one of the first countries to develop AK-47 derived assault rifles. The Valmet M76 was based on the AK-47 and was designed for use in cold Arctic conditions. Though the M76 uses the same gas-mechanism of the AK-47, its construction differs significantly in terms of the materials and the technique used.

The Valmet M76 is available in different butt configurations. Versions with a foldable and fixed stock are also available. Fixed stock versions come with either a conventional solid stock or with a steel pipe stock.

The rifle feeds from 15, 20 or 30-round detachable box magazines. The trigger guard of the rifle can also be easily removed to enable firing with a gloved finger in the cold Artic conditions. Like all other derivatives of its parent rifle i.e. the AK-47, the Valmet is very rugged and reliable even in the most extreme conditions.

Some versions and variants of the Valmet M76 have also been developed. Most notable of these is the M78. This rifle is designed as a squad support weapon and has a comparatively heavier barrel and a bipod mounting. Other than these differences, it is very much similar to the M76.

The Valmet M76 is currently being used by Finland, Qatar and Indonesia.

The Vector R4 is a 5.56 mm assault rifle of South African origin. The Vector R4 is loosely based on the Israeli Galil rifle and has several modifications over its parent weapon.

The Vektor R4’s design began when South Africa was subjected to an international arms embargo during the apartheid era. This led to the development of an indigenous arms industry in South Africa.

The Vektor R4 has several innovative features. Though the rifle bigger in size that the Israeli Galil, it weight almost the same because of its of high-density polymers in the construction.

The R4 also has some incongruous features like an inbuilt bottle opener. Though this feature may seem useless, it is nevertheless useful as many soldiers often use the sharp projections of their rifles to open beer bottles, often causing damage to the rifle.

The Vektor R4 is designed to use the 5.56x45mm NATO round and feeds from a 35-round detachable box magazine. It is accurate up to 300 to 500 meters.

A few variants of the R4 have also been developed. These include the R5 and R6. The R5 is a carbine version of the R4. The R6 is a much shorter version of the R4.

The AKS-74 is an assault rifle designed by Mikhail Kalashnikov in the early 1970s. The design of the AKS-74 is based on the earlier AKM and is chambered for the 5.45x39mm round.

The AKS-74 was designed for use by air assault infantry and thus features a side-folding metal stock to reduce size. The stock is made from stamped steel assembled using welding and thus is very robust.

On the minus side, the AKS-74 has a large muzzle flash which is a drawback. In addition, the fully-automatic fire is also somewhat random. However at close quarters, the rifle is very effective.

Several variants have been developed on the basis of the AKS-74. One such variant is the AKS-74U. This rifle is a shorted versions designed primarily for use by Special Forces. The rifle’s small dimensions were achieved by making modifications to both the barrel and also the gas-receiver system.

The AKS-74U is set to be replaced by newer members of the Kalashnikov family namely the AK-105. Other variants in the series i.e. AK-101, AK-102, AK-103 and AK-104 are also based on the AK-74.

The AKM is an upgraded version of the AK-47. It was designed by Mikhail Kalashnikov in the 1950s and was adopted by the Red Army in 1959. The AKM is one of most widely used assault rifles. Many Warsaw Pact countries and other countries in Asia and Africa field the AKM rifle. The rifle is manufactured at Izhevsk Mechanical Works and Tula Arsenal.

When compared with the AK-47, the AKM has several enhancements. The AK-47 has a stamped steel receiver which makes it very cheap to manufacture. However, this creates reliability problems. To answer this problem, prototypes were created with machined received. However this made production costs higher and so it was decided to switch back to stamped steel receivers albeit with higher quality requirements. This resulted in the AKM.

In addition, the AKM also had a redesigned muzzle that acts a crude muzzle brake. Some of the escaping gas is deflected upwards which stabilizes the gun during fire. The AKM is designed to fire the same round as the AK-47—the 7.62x39mm.

The AKM can be distinguished easily from the AK-47 by a recess above the magazine housing.

Several versions and variants of the AKM have been designed. These include AKMP, AKML, AKMLP, AKMSP, AKMSN and the AKMSNP.

The Walther WA 2000 is a semiautomatic sniper rifle designed by Carl Walther GmbH Sportwaffen. The rifle was originally designed to be used as a target rifle. However, the rifle became very popular as a sniper rifle.

The WA 2000 used a bullpup design. This design was used because it would help in reducing the overall length of the rifle and yet retain the long barrel length needed to ensure accuracy and range of the bullet. In addition, the rifle also comes with the PV4 aiming optics which allows night vision.

The rifle was designed to use the .300 Winchester Magnum round. The calibre was chosen because of its long range and high accuracy. The rifle fires from a closed-bolt and used seven locking lugs. It feeds from a 6-round detachable box magazine.

The Walther WA 2000 was an experimental weapon. In total, only 176 rifles were manufactured. These included versions chambered for the 7.62x51mm NATO and the 7.5x55mm Swiss cartridges in addition to the .300 Winchester. Production of the rifle was completely stopped in 1988 due to high manufacturing costs.

Of the 176 units manufactured, 15 were exported to the United States. Today, the WA 2000 is a rare weapon. Because of its rarity, it can fetch up to $80,000 in the open market.

The Heckler & Koch PSG1 is a sniper rifle developed by Heckler & Koch in Germany. PSG stands for “Prazisionsscharfschutzengewehr” which means “precision sharpshooter rifle” in German.

The PSG1 was designed in response to the West German Police Force’s failure during the 1972 Summer Olympics incident. The Police failed to kill the terrorists fast enough and all the hostages were killed. Heckler & Koch was then approached to design a highly accurate, semiautomatic sniper rifle for military and police use.

The PSG1 is chambered for the 7.62x51mm NATO cartridge and feeds using a 5 or 20-round detachable box magazine. It has an effective range of 800 meters. Overall the gun weighs 7.2 Kg.

The rifle features high-quality aiming optics. It is mounted with the Hensoldt 6x42 scope. The aiming optical scope has an inbuilt range adjuster which allows the scope to be tuned from 100 to 600 meters.

The barrel of the rifle is very heavy. The stock is made from high-strength polymer and can be adjusted to suit the firer’s profile. In addition, the rifle also comes with a vertically-adjustable cheek piece.

One of disadvantages of the PSG1 is that it is difficult to reload. In addition, the spent case of the bullet is also ejected with a lot of force which causes it to travel distances up to 10 meters or so. Though, this is not an issue in police combat, it can reveal the position of the sniper in the field, thus making him/her an easy target.

The Heckler & Koch PSG1 is very costly to produce and retails at a high price of $15,000 to $20,000. There are fewer than 400 units of the PSG1 in the United States due to import regulations and the high price tag. In Germany, the PSG1 is used by the Spezialeinsatzkommando.

The Barrett 82A1 Light Fifty is a .50 calibre anti-material sniper rifle. It is recoil-operated and fires in semi-automatic mode. It was designed by Ronnie Barrett and is manufactured by Barrett Firearms Manufacturing. It is used by many countries across the globe.

Barrett Firearms Manufacturing was started by Ronnie Barrett to manufacture rifles capable of firing the high-power 12.7x99mm NATO ammunition. He designed the first rifle in 1982 and thus the rifle is designated as M82. Several improvements were made subsequently to the initial design. The version is designated as M82 A1.

The first country to adopt the M82 A1 was Sweden. Subsequently, the United States Army adopted the rifle during the First Gulf War. Today, more than 30 countries such as Brazil, Denmark, Germany, Israel, Italy, Norway and many others use the M82 rifle.

The massive round fired by the M82 has very high stopping power. It is commonly used against material targets like helicopters, light vehicles and aircraft. It is also used to destroy enemy targets of strategic value such as radar and radio communication systems.

The M82A1 is very heavy at 14.7 Kgs and is also very long. When compared to the M16 rifle, the M82 is four times as much heavy and one and half times longer. It uses an 11-round box magazine as its feed system and comes with an integral bipod.

When compared with other rifles, the Barrett M82A1 is very costly. It is not designed for the ordinary soldier. In the hands of an experienced sniper, the M82A1 can be very effective in paralysing enemy operations and communication systems from beyond the reach of the enemy.

The SVD Dragunov is a Soviet sniper rifle based on the AK-47 action. It saw wide deployment in numerous conflicts and was adopted by the armies of many Warsaw Pact countries.

Unlike many other countries, the Soviet Union placed high emphasis on snipers. The SVD was thus designed to equip the marksmen. The Dragunov was an excellent weapon in the right hands.

The Dragunov is loosely based on the AK-47. However, it is chambered for the 7.62mmR round. The ammunition of the Dragunov is not compatible with other standard infantry rifles.

The rifle has a heavier barrel and is accurate up to 800 meters. The rifle was very light for a sniper’s rifle. However like all other Soviet rifles, it was very robust and reliable in the field.