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124-461: The tank's full name is Floating Tank–76 ( плавающий танк , plavayushchiy tank , or ПТ-76 ). 76 stands for the caliber of the main armament: the 76.2 mm D-56T series rifled tank gun . The PT-76 is used in the reconnaissance and fire-support roles. Its chassis served as the basis for a number of other vehicle designs, many of them amphibious, including the BTR-50 armored personnel carrier,

248-458: A circular error probable method that assumes a 50% hit probability (R 50 ) and cannot be converted and is not comparable to US military methods for determining small arms accuracy. When the R 50 results are doubled the hit probability increases to 93.7%. The PKB is a variant of the PK that has been designed for use as a pintle mounted machine gun on combat vehicles. A swivel has been attached to

372-543: A circular error probable method that assumes a 50% hit probability (R 50 ). For heavier employment, the PKS (ПК Станковый: "PK Mounted") is based on the Samozhenkov 6T2 tripod mount. The PK and 6T2 tripod weigh 16.5 kg (36.38 lb). The 6T2 Samozhenkov general-purpose tripod mount was designed by E. S. Samozhenkov and entered service in 1961 and weighs 7.5 kg (16.53 lb). The 6T2 Samozhenkov tripod mount

496-488: A direct fire mode to defeat a variety of ground targets at all ranges, including dug-in infantry, lightly armored vehicles, and especially other heavily armored tanks. They must provide accuracy, range, penetration, and rapid fire in a package that is as compact and lightweight as possible, to allow mounting in the cramped confines of an armored gun turret . Tank guns generally use self-contained ammunition, allowing rapid loading (or use of an autoloader ). They often display

620-601: A hull down fire position on higher ground. One of the greatest disadvantages of the gun used on the PT-76 Model 1 was that it had no stabilization system and therefore couldn't be effectively fired while the vehicle was on the move. The PT-76 Model 2 has a 1-axis stabilization system and the PT-76B has a 2-axis system. The armor of the PT-76 consists of homogeneous, cold-rolled, welded steel. Its turret has 20 mm at 35° at

744-460: A Warsaw Pact side-rail bracket on the left side of the receiver can mount various aiming optics. The standard Russian side rail mounted optical sight was the 4×26 1P29 Universal sight for small arms, an aiming optic similar to the British SUIT and SUSAT and Canadian C79 optical sights . When mounted, the 1P29 sight is positioned centered above the receiver at a height that allows the use of

868-724: A bulge in the barrel, which is a bore evacuator , or a device on the muzzle , which is a muzzle brake . The first tanks were used to break through trench defences in support of infantry actions particularly machine gun positions during the First World War and they were fitted with machine guns or high explosive firing guns of modest calibre. These were naval or field artillery pieces stripped from their carriages and mounted in sponsons or casemates on armored vehicles. The early British Mark I tanks of 1916 used two naval 57 mm QF 6 pounder Hotchkiss mounted either side in sponsons. These guns proved too long for use in

992-538: A cupola on the left side of the double hatch. The cupola has the TPKU-2B observation device and two TNP day periscopes and can be rotated 360 degrees by hand. The commander also has a 4X optical sight mounted to the left of the main armament and a TShK-66 sight/rangefinder. The loader has the MK-4 observation device mounted on the turret's roof in front of the hatch. The BM-354P High Velocity Armor Piercing ( HVAP ) round has

1116-484: A direct hit on the turret of a M48, killing two crewmen and wounding two more. A second M48, using the same technique, destroyed a PT-76 with their second shot. At daybreak, the battlefield revealed the wreckage of two PT-76s and one BTR-50 armored personnel carrier. The PT-76 was involved in a landmark incident in armored warfare, in being the first victim of the BGM-71 TOW anti-tank missile . On April 24, 1972,

1240-772: A few PT-76 tanks. During the Yom Kippur War in 1973 PT-76s were used during the crossing of the Great Bitter Lake by the Egyptian 130th Marines Brigade. The People's Armed Forces of Liberation of Angola (FAPLA) deployed PT-76s during the Angolan Civil War , as did Cuba during its lengthy military intervention in that country. One FAPLA PT-76 was destroyed by a South African Ratel-90 armoured car during Operation Moduler . At least six others were captured by South African expeditionary forces over

1364-545: A front-line infantry and vehicle-mounted weapon with Russia's armed forces and has also been exported extensively and produced in several other countries under license. The Main Artillery Directorate of the Soviet Union (GRAU) adopted specification requirements for a new 7.62 mm general-purpose company and battalion-level machine gun that was to be chambered for a rifle cartridge in 1955. In 1958

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1488-406: A fume extractor for the main gun at the rear of the turret. The 7.62 mm SGMT coaxial medium machine gun comes with 1,000 rounds. This weapon has a maximum effective range of 1,000 meters in daylight while the vehicle is stationary, 400 to 500 meters in daylight while the vehicle is on the move and 600 meters at night. Maximum range is 1,500 meters. It can be fired in 2 to 10 round bursts and has

1612-416: A gas regulator and an electric solenoid trigger. The PKT minimum cyclic rate of fire is 100 rounds per minute higher than other PK-series variants and is usually fed from 250-round ammunition boxes. The PKT barrel assembly weighs 3.23 kg (7.1 lb) and can fire up to 500 rounds in rapid fire scenarios before it has to be replaced for another barrel or allowed to cool down to prevent unacceptable wear of

1736-405: A latch is mounted in the rear part of the bolt carrier assembly. The cocking lever, mounted on the right, is not integral with the bolt carrier and does not reciprocate as the gun fires. The gas cylinder is mounted under the barrel and fitted with a gas regulator with three fixed positions. The gas regulator opens corresponding holes to change the amount of expanding propellant gases bled off out of

1860-614: A machine gun prototype the Nikitin-Sokolov PN1, developed by G.I. Nikitin and Yuri M. Sokolov, successfully passed field tests. Based on the results of the tests it was decided in 1960 to manufacture a batch of Nikitin-Sokolov machine guns for service tests and then put the machine gun into production at the Kovrov Mechanical Plant. However, the weapon had some flaws, the main flaw being that the weapon did not resist water and snow very well. Water and snow had

1984-448: A maximum effective range of 650 meters by day and 600 meters at night. Its maximum aimed range is 1,060 meters. It can penetrate 127 mm of armour at muzzle and 50 mm at 1,000 meters. The armour-piercing round can pierce 60 mm of armor inclined at 60 degrees from a range of 2,000 meters. The BK-350M High Explosive Anti Tank or HEAT round has a maximum effective range of 650 meters by day and 600 meters at night. Its maximum range

2108-476: A practical rate of fire of 250 rounds per minute and a cyclic rate of fire of 650 rounds per minute. From 1967, the machine gun was replaced with PKT of the same caliber. The main gun, which is considered light for a modern tank, can fire BM-354P HVAP, API-T, AP-T, BR-350 API-T and OF-350 Frag-HE rounds (as can the 76.2 mm M1942 (ZiS-3) divisional gun) and is capable of penetrating the armour of APCs and other lightly armored vehicles. The commander/gunner has

2232-421: A rod-and-screw elevation mechanism. The traversing mechanism is fitted with stops to limit the field of fire. For anti-aircraft fire or fire against ground targets from a kneeling position the cradle mounts a collapsible pole with a pivoting bracket. The mount features non-digging-in spades — sliding spades affect the accuracy of fire less than a "jumping" tripod with dug-in spades. There is an extra folding spade on

2356-435: A tendency to enter the gas piston. If, after firing, the machine gun was in the water, then after two or three shots the machine gun could fire exclusively only shot by shot. After a single shot, the shooter had to reload the weapon and move the slide manually two or three times. The army therefore asked Nikitin to solve this problem, but the engineer took too long to resolve this problem. In order to force Nikitin to work faster,

2480-433: Is 1,000 meters. It can penetrate 280 mm of armour at 1,000 meters. The OF-350 Frag-HE round has a maximum effective range of 600 meters at night and a maximum range of 4,000 meters. The gun can be fired while the vehicle is afloat. The gun can also be depressed and elevated between −4 and +30 degrees so like most Soviet tanks, the PT-76 has a limited ability to depress its main gun, and therefore can have difficulty finding

2604-415: Is 42 calibers long. The PT-76 carries 40 rounds for its gun. A typical ammunition load consists of 24 x OF-350 Frag-HE, 4 x AP-T, 4 x API-T and 8 x BK-350M HEAT rounds (with AP-T rounds substituted for HVAP when available). The gun is mounted in an oval dish-type circular truncated cone turret with flat, sloping sides which is mounted over the second, third, and fourth pair of road wheels. All PT-76s have

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2728-624: Is a belt-fed general-purpose machine gun , chambered for the 7.62×54mmR rimmed cartridge. Designed in the Soviet Union and currently in production in Russia, the original PK machine gun was introduced in 1961 and the improved PKM variant was introduced in 1969. The PKM was designed to replace the SGM and RP-46 machine guns that were previously in Soviet service. The weapon remains in use as

2852-531: Is equipped with a lever-type feed mechanism introduced in Louis Stange 's MG 39 Rh and copied in the Czechoslovak machine guns like vz. 52 and vz. 59 , which is operated by the feed lever. The lever, which is simplified compared to the prior art, is mounted on the right wall of the receiver and wraps around the bolt carrier with its feed pawl and roller. The rest of the mechanism is mounted either on

2976-528: Is equipped with a tank communication device, a gyro compass, a 10-RT-26E radio with an antenna that extends itself when needed. It also has two headlights in front of the hull and a searchlight on the right-hand side of the top of the turret. It lagged behind other Soviet armoured fighting vehicles because only the driver had a night vision device and also because it has no fire or NBC (nuclear, biological, chemical) protection systems, which significantly reduced its effectiveness. The lack of NBC protection ended with

3100-401: Is hinged to the bolt carrier assembly, and its vertical travel makes it possible to bend the group making machine gun assembly and disassembly for maintenance easier. The protruding rear part of the bolt carrier assembly features spiral shaped cuts, which provide a controlled rotation of the bolt. The mainspring is accommodated in the bolt carrier assembly slide channel. A cartridge extractor with

3224-416: Is improved over earlier weapons by computerized fire-control systems, wind sensors, thermal sleeves , and muzzle referencing systems which compensate for barrel warping, wear and temperature. Fighting capability at night, in poor weather, and smoke was improved by infrared , light-intensification , and thermal imaging equipment. Technology of the guns themselves has had only a few innovations. For decades

3348-437: Is limited; for extremely long ranges cannon-launched guided projectiles (CLGPs) are considered more accurate. The use of the autoloader has been a development favoured by some nations and not others. Some countries adopted it as a means to keep the overall size of the tank down. Interest has also been shown as a means to protect the crew by separating them further from the gun and ammunition. For example, an autoloader allows

3472-626: Is part of the Murmansk military district and 336th Belostokskaya marine brigade (26) from Baltyysk, which is part of the Kaliningrad military district. In Ludowe Wojsko Polskie (LWP), PT-76s and PT-76Bs were used by the reconnaissance subunits of tank divisions and mechanized divisions and Coastal Defense units including the 7th Lusatian Landing Division (officially known as 7th Coast Defense Division). Poland also operated FROG-3 "Luna" tactical missile launch vehicles. PT-76s were in service with

3596-558: Is put on an AA mount. As with all general-purpose machine guns, tripod and vehicle mountings offer a higher degree of accuracy and control than when used on a less stable bipod. The PK machine gun, firing short bursts from a bipod, as a light machine gun has the following accuracy of fire: a mean deviation of 7–10 cm (2.8–3.9 in) at a range of 100 m (109 yd), 37–51 cm (15–20 in) at 500 m (547 yd), and 71–103 cm (28–41 in) at 1,000 m (1,094 yd). The Russian and other European militaries use

3720-467: Is riveted onto the receiver cover and consist of a square notched rear tangent iron sight calibrated in 100 m (109 yd) increments from 100 to 1,500 m (109 to 1,640 yd) and includes a " point-blank range " battle zero setting corresponding to a 330 m (361 yd) zero. It is identical in design to the AKM and Mosin–Nagant , except that it is oriented backwards with the notch forward and

3844-466: Is still on active service in a number of countries mainly in the developing world . The Russian Army is reported to have used PT-76 units in the war in Chechnya . The PT-76 is used/stationed by/in following Russian units/bases: 61st tank repair plant (1), 61st Kirkinesskaya marine brigade (26) from Sputnik, which is part of the Murmansk military district, 175th marine brigade (26) from Tumannyy, which

PT-76 - Misplaced Pages Continue

3968-409: Is the stripping procedure performed to remove those mechanisms from the gun for cleaning. The bolt and bolt carrier are however oriented upside down compared to the AKM, with the piston and gas system being underneath the barrel. Unlike the AKM and RPK the PK machine gun series is an open bolt design, which improves heat management during automatic fire compared to closed bolt designs and helps avoiding

4092-576: The 7.62×54mmR Eastern Bloc standard cartridge that produces significantly more bolt thrust when compared to the Eastern Bloc 7.62×39mm and 5.45×39mm intermediate cartridges . With the use of a single spare parts kit and two barrel assemblies the service life of the modernized PKM machine gun series is guaranteed for at least 25,000 rounds. The bolt and carrier design are similar to the AK-47 and other modernised Kalashnikov-pattern weapons, as

4216-826: The Central Asian , Odessa , and Baltic Military Districts , as well as at the Vystrel officer training courses in late 1960. The Main Missiles and Artillery Directorate and the Ministry of the Defence Industry preferred the Kalashnikov design. The PK could resist water perfectly, but it was also much easier to maintain and manufacture, because it reused the same ammunition bands as the Maxim or SG-43 , while

4340-446: The MG 42 feed mechanism that typically incorporate a much larger (and therefore much heavier) articulated feed cam, lever, and pawl assembly that pushes rimless cartridges out forward from their links directly into the chamber for firing. The PK fires from the rear sear. The breech is locked by a rotating bolt, with two locking lugs engaging locking recesses in the receiver. The gas piston

4464-621: The QF 2-pounder (40 mm) and 37 mm equipped British cruiser tanks and infantry tanks in the late 1930s. These weapons lacked a good high-explosive shell for attacking infantry and fortifications, but were effective against the light armor of the time. World War II saw a leapfrog growth in all areas of military technology. Battlefield experience led to increasingly powerful weapons being adopted. Guns with calibres from 20 mm to 40 mm soon gave way to 50 mm, 75 mm, 85 mm, 88 mm, 90 mm, and 122 mm calibre. In 1939,

4588-721: The SU-100 ). The relative superiority in armament of tank destroyers was only relative, however: for instance, the SU-85 was a casemate-type TD on the T-34 chassis that was rendered obsolete once the basic T-34 switched from the 76 mm gun to the same 85 mm cannon, producing the T-34-85 . By the end of the war the variety in tank designs had narrowed and the concept of the main battle tank emerged. The race to increase caliber slowed, with just slight increases between tank generations. In

4712-633: The ZSU-23-4 self-propelled antiaircraft gun, the ASU-85 airborne self-propelled gun and the 2K12 Kub anti-aircraft missile launch vehicle. After World War II, the concept of light tanks was resurrected in the USSR. They were to be used in reconnaissance units and therefore an amphibious ability was essential. The requirements stated that the vehicle should be able to cross water obstacles with little preparation. Many prototypes of such light tanks were built in

4836-455: The 120 mm Royal Ordnance L11A5 rifled gun until the 1990s; it was then replaced it with the 120 mm L30 rifled gun which remains in service. The Indian Arjun tank uses an Indian-developed 120 mm rifled gun. PK machine gun The PK ( Russian : Пулемёт Калашникова , transliterated as Pulemyot Kalashnikova , or "Kalashnikov's machine gun") also commonly known as the PKM ,

4960-523: The American offensive and mobile reserve model, which favoured lightly-armed open-top vehicles with a rotating turret and a powerful anti-tank-capable gun while relegating true tanks to infantry support role (exemplified by the M10 tank destroyer ); and the casemate gun mount model, which often allowed the resultant vehicle to be hard to hit and have a well-sloped and heavily armoured glacis plate (for instance,

5084-518: The British tank designs as they would come into contact with obstacles and the ground on uneven terrain, and the succeeding Mark IV tank of 1917 was equipped with the shortened 6 pounder 6 cwt version which can be considered the first specialised tank gun. The first German tank, the A7V , used British-made 57 mm Maxim-Nordenfelt fortification guns captured from Belgium and Russia, mounted singly at

PT-76 - Misplaced Pages Continue

5208-580: The Indian Army and they were in reserve status before they were withdrawn from service in 2009, after which they were used for target practice by the army and as static memorials at various military facilities. Soviet PT-76s along with T-54s , T-55s , and Chinese Type 59s tanks formed the bulk of the People's Army of Vietnam (PAVN) armored forces. The first successful action of PAVN armor in Vietnam

5332-521: The M48 fired three 90 mm rounds; obtaining a hit with the third round. The tank crew abandoned their vehicle. Shortly afterwards, some returning F-4 Phantom jet fighter bombers, with ordnance to expend, observed the PT-76 and bombed the remainder of the vehicle. The Battle of Ben Het was the only PAVN–US Army tank battle during the course of the Vietnam War. 10 PT-76s faced 3 M48s. On March 3, 1969,

5456-480: The Main Artillery and Missile Directorate decided in 1958 to restart the competition. For that a team of Izhevsk Mechanical Plant designers, headed by M.T. Kalashnikov , and further consisting of V.V. Krupin, V.N. Pushchin, A.D. Kryakushin, as well as Startsev, Kamzolov, Koryakovtsev, Yuferev, joined the competition. Kalashnikov and his team accepted the task while at the same time, they were already working on

5580-686: The Nikitin-Sokolov prototype machine gun. Nikitin's and Sokolov's machine gun design was later used in the 12.7 mm NSV heavy machine gun that was put into production in 1971. In June 2024, it's reported that the PKZ will eventually replace the PKM in Russian military service. The original PK was a development of Kalashnikov 's AKM assault rifle and the accompanying RPK light machine gun design that featured stamped receivers. The PK uses

5704-416: The PK are further normally issued with several quick change barrels that during prolonged intense use are swapped out allowing one barrel to cool while the machine gun fires with the other. The rimmed 7.62×54mmR cartridges are set in a metal ammunition belt and are held against the shoulder inside non disintegrating looped links, leaving the rim exposed at the rear. The belt is mounted from the right side into

5828-500: The PK feeds from the right and ejects its spent cases via an ejection port on the left side of the weapon, contrary to the right side ejection port seen in most Western machine guns. For the light machine gun role, the PK is used as the standard squad automatic weapon of the Russian Army. The PK uses a 100-round non-disintegrating belt contained in a metal box made from an aluminium frame and steel cover that can be attached under

5952-463: The PK machine gun series is the 4×24 1Р77. The trigger assembly, mounted inside the receiver, is operated by the mainspring and suitable for automatic fire. It has no single shot mode of fire. The manual rotating type safety locks the sear, which engages the sear notch of the bolt carrier assembly, and the trigger lug does not allow the bolt carrier assembly to go all the way back. The skeletonized buttstock, pistol grip and folding carry handle/grip on

6076-506: The PKMN. The PKMSN variant can use NSPU-3 ( 1PN51 ) and NSPUM (1PN58) night sights. It can also be fitted with the 1PN93 series passive night sights. Besides that Shakhin and 1PN116 thermal sights and the 1PN119 anti-sniper special-purpose night vision sight are available for mounting on PK machine guns that like the PKMSN model feature a Warsaw Pact side-rail bracket on the left side of

6200-452: The PN1 used a new type of bands which was not yet in production at the time. Furthermore, according to Kalashnikov, its competitors attempted to bias the test by asking operators to lower the rate of fire because of overlapping bands during long bursts. There was also another incident during the test, according to Kalashnikov, the recoil of the PN1 was poorly distributed and a large part ended up in

6324-484: The PT-76B, which has the PAZ ("protivo-atomnaya zashchita") NBC protection system. Because only the driver has night vision equipment, the crew has a vision range of 4,000 m (13,000 ft) by day and 600 m (2,000 ft) at night. About 5,000 PT-76s were built during the vehicle's lifetime, of which some 2,000 were exported. Other sources indicate that 12,000 were built. (See footnote 1). Over 25 countries employed

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6448-581: The Special Forces' Ben Het Camp was attacked by the PAVN 202nd Armored Regiment. The 202nd was given the task of destroying the camp's 175 mm self-propelled guns. One of the PT-76s had detonated a land mine, which not only alerted the camp, but also lit up the other PT-76s attacking the firebase. Flares had been sent up, thus exposing adversary tanks, but sighting in on muzzle flashes, one PT-76 scored

6572-454: The TOW team destroyed 3 PT-76s and broke up the attack. On May 26, the PAVN made another attempt to retake the city of Kontum . TOW aircraft were brought in at first light and found PAVN tanks moving almost at will through portions of the city. Conventional air strikes would have been risky for friendly forces, and the TOW proved to be ideal for picking off enemy tanks. At the end of the first day,

6696-459: The U-shaped stamping. The receiver top cover is also stamped from 1.5 mm sheet metal and hinged on the front of the receiver and locked at the back with a spring-loaded latch. The quick detachable barrel assembly slides into the receiver and attaches by a barrel-lock. On the original PK it was partially fluted to increase rigidity and improve heat dissipation. The barrel-lock also regulates

6820-708: The US special experimental 1st Combat Aerial TOW Team arrived in South Vietnam. It consisted of two UH-1B helicopters mounting the new BGM-71 TOW and technicians from Bell Helicopters and Hughes Aircraft Corporation . It deployed in the Central Highlands , where it commenced gunnery training. From May 2, the team made daily flights in search of enemy armor, with the missiles mounted in the XM26 three-tube launcher. On May 9, PAVN armored units attacked Ben Het Camp;

6944-707: The Watervliet Arsenal for the US Abrams M1A1 tank using de Graffenried's patented high-precision manufacturing inventions. Based on their experience with the 2A28 Grom gun/missile system of the BMP-1 , the Soviets produced the T-64 B main battle tank, with an auto-loaded 2A46 125 mm smoothbore high-velocity tank gun , capable of firing APFSDS ammunition as well as ATGMs. Similar guns continue to be used in

7068-560: The West, guns of around 90 mm gave way to the ubiquitous 105 mm Royal Ordnance L7 , introduced in 1958. This lasted a long while, with a shift to 120 mm in the late 1970s and early 1980s (the UK changed in the late 1960s with their Chieftain tank). In the East, the 85 mm quickly yielded to the 100 mm and 115 mm U-5TS gun, with the 125 mm caliber now standard. Most of

7192-401: The accuracy of fire. Besides, the almost entirely from steel stampings made Stepanov mount has 20 fewer components than the preceding Samozhenkov tripod and is 40% less labour-intensive, simplifying and rationalizing production. The Stepanov mount is based on a principle of multi-functional components: the elevation mechanism frame is also used as a pole for kneeled shooting or anti-aircraft fire;

7316-473: The air temperature is −20 °C or colder). The PT-76 has a 5-speed manual shaft-type transmission system similar to the one in the T-34/85 . The gearbox has four forward gears and one reverse. The vehicle has a side clutch that enables it to make turns and a handbrake. The tank has four mounts for additional external fuel tanks at the rear of the hull. The two on the corners are for flat type external tanks and

7440-426: The average tank had to grow as well to carry the ammunition, mounting, and protection for these powerful guns. While high velocity tank guns were effective against other tanks, for the most part British tanks moved to a dual purpose 75 mm gun capable of firing a useful HE shell; later in the war adding 76 mm 17pdr gun armed tanks for better antitank capability. Many nations devised " tank destroyers " during

7564-408: The barrel and in that light machine gun setup is used as a squad-level support weapon. The right bipod leg accommodates links of a cleaning rod. Other accessories include a sling and storage covers. The PK machine gun is also suitable for installation on tripod mounts or vehicle mounted medium machine gun setups and can also be used as a light anti-aircraft weapon against slow flying aircraft when it

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7688-408: The barrel of the main gun and serves as additional armor. Bilge pumps keep the tank afloat even if it leaks or is damaged. There is a manual bilge pump for emergency use. The tank is propelled through the water by two hydrojets, one on each side of the hull, with the inlets underneath the hull and the outlets at the rear. There are also additional assistant water-jet inlets on both sides of the hull over

7812-409: The barrel. The PKM barrel assembly weighs 2.4 kg (5.3 lb) and can fire up to 400 rounds in rapid fire scenarios before it has to be replaced for another barrel or allowed to cool down to prevent unacceptable wear of the bore. The sustainable effective rate of fire is about 250 rounds per minute. Whilst, the cyclic rate of fire is around 600–800 rounds per minute. The rear sight assembly

7936-402: The barrels were originally manufactured from birch plywood laminates . Such engineered woods are stronger and resist warping better than the conventional one-piece patterns, do not require lengthy maturing, and are cheaper. The wooden furniture was finished with the Russian amber shellac finishing process. Small accessories and an oil-solvent container can be stored inside butt recesses. Later

8060-405: The base sleeve also serves as the axis for attaching rear legs of the tripod: the machine gun attachment is combined with the elevation mechanism frame lock for anti-aircraft fire; the fine elevation adjustment mechanism is integrated with the elevation mechanism axis. Each tripod leg can be folded for transport or adjusted for proper height on uneven terrain. The ammunition belt box can be secured to

8184-424: The bore. Some PKTs have been converted to infantry machine guns. The PKM (ПК Модернизированный: "Kalashnikov's Machine-gun Modernised"), was adopted into service in 1969. The PKM is a modernised, product-improved version of the PK. The upgrades are primarily aimed at reducing the weight, simplifying production, and facilitating easier operation. The receiver cover became more rigid due to lengthwise ribs. The butt

8308-409: The buttstock was fitted with a hinged butt-rest. More recent PKM machine guns and barrel assemblies are equipped with a new black glass-filled polyamide buttstock, pistol grip and barrel carry handle/grip shaped like the previously used laminated wooden stock and grips. PK machine guns are belt-fed, using non-disintegrating metal belts , which have links that wrap around the cartridge case shoulder all

8432-465: The code-name PKM-NATO (or PKM-N). The modifications included a heavier barrel, a larger chamber, and a redesign of the lock, bolt, extractor, and the entire feeding mechanism. The prototype was tested from 1997 to 1999, but was rejected. The Polish Army adopted the UKM-2000 machine gun instead in 2007, which was also based on the PKM. The Zastava M84 is a Yugoslav/Serbian-made licensed copy of

8556-867: The course of that conflict. During the Yugoslav wars , the PT-76 served with the Yugoslav People's Army and later the army of the Krajina Serbs in a few battles during the Ten-Day War in Slovenia (1991) and Croatian War of Independence (1991–1995). The Indonesian Marine Corps used its PT-76Bs on the Indonesian island of Ambon during Maluku sectarian conflict in 1999-2003, and also in mid 1970s during Operation Lotus ( Operasi Seroja ). Background: History of

8680-509: The dangerous phenomenon known as " cook-off ", wherein the firing chamber becomes so hot that the propellant contained in a chambered round unintentionally ignites, making the weapon fire until the ammunition is exhausted. Open bolt designs typically operate much cooler than closed bolt designs due to the airflow allowed into the chamber, action and barrel during pauses between bursts, making them more suitable for constant full-automatic weapons such as machine guns . General-purpose machine guns like

8804-593: The dawn of World War II , when most tank guns were still modifications of existing artillery pieces, and were expected to primarily be used against unarmored targets. The larger caliber, shorter range artillery mounting did not go away however. Tanks intended specifically for infantry support (the infantry tanks ), expected to take out emplacements and infantry concentrations, carried large calibre weapons to fire large high-explosive shells—though these could be quite effective against other vehicles at close ranges. In some designs – for example, M3 Lee , Churchill , Char B1 –

8928-605: The design of the AKM and the RPK . Kalashnikov accepted the task despite his workload and the fact that Nikitin's PN1 had already been chosen by the army and that the latter was supported by certain ministries and senior officers. Their machine gun prototype was based on the well-proven gas-operated rotary-bolt design of the Kalashnikov-pattern arms. The Kalashnikov and the Nikitin-Sokolov prototypes underwent service tests in

9052-484: The difference in operation between smoothbore and rifled guns shows in the type of secondary ammunition that they fire, with a smoothbore gun being ideal for firing HEAT rounds (although specially designed HEAT rounds can be fired from rifled guns) and rifling being necessary to fire HESH rounds. Most modern main battle tanks now carry a smoothbore gun. A notable exception are the tanks of the British Army which used

9176-462: The drive sprocket at the rear and the idler at the front. The road wheels are hollow to minimize weight. These hollow road wheels increase the tank's buoyancy by 30%. There are no track-return rollers. The first and last road wheels have a hydraulic shock absorber and the steel tracks have 96 links each when new, each link has a single pin. There is a small, thin, horizontal skirt over each track. Its straight 6-cylinder, 4-stroke water-cooled diesel engine

9300-411: The driver's seat, there is an emergency hatch that can be used by all crew members. At night, the center periscope is swapped for a TVN-2B night vision device which gives the driver clear vision up to 60 meters. Its main armament consists of a 76.2 mm D-56T series rifled tank gun, which has an effective range of approximately 1,500 meters and a rate of fire of six to eight rounds per minute. This gun

9424-433: The entrance took out three PT-76s until it was knocked out), and ineffectively with M72 LAWs (one-shot disposable 66 mm Light Anti-Tank Weapon). They requested support from nearby Khe Sanh Combat Base , which was unable to help, as it too was under siege. The Lang Vei camp was overrun, with the PT-76s using their turret-mounted spotlight-equipped heavy machine guns to shoot down any irregulars who panicked and ran out of

9548-415: The feed way of the PK machine gun. The PK uses a non-reciprocating charging handle on the right side of the receiver to charge the gun. Since the PK uses a rimmed rifle cartridge and closed-link belts used for feeding, a two-stage feed mechanism with a preliminary extraction of a cartridge from a belt link was preferred over a direct ammunition feed design often used for rimless cartridges. The PK machine gun

9672-541: The first wave of an attack and for artillery support during the establishment of a beachhead. The main disadvantage of the BMP-1 and the BRM-1 when compared to the PT-76 is the absence of a powerful main armament. However, the BRM-1 is fitted with more modern reconnaissance equipment. Also, both vehicles have stronger front armor and superior mobility features and the BMP-1 can carry up to 8 fully equipped soldiers inside. The PT-76

9796-580: The front leg for slippery and moving ground. Hinged tripod legs allow a gunner to fire the machine gun from a prone, a sitting, or a kneeling position. The PKS machine gun, firing bursts from its tripod with fixed traversing and elevation mechanisms, as a medium machine gun has the following accuracy of fire: mean deviation of 5–6 cm (2.0–2.4 in) at a range of 100 m (109 yd), 25–29 cm (9.8–11.4 in) cm at 500 m (547 yd), and 49–68 cm (19–27 in) at 1,000 m (1,094 yd). The Russian and other European militaries use

9920-623: The front, 16 mm at 35° at the sides, 11 mm at 33° at the rear and 8 mm at 0° on top of the turret. The hull is made up of: 10 mm at 80° at the upper front, 13 mm at 80° at the lower front, 14 mm at 0° at the sides, 7 mm at 0° in the rear and 5 mm at 0° underneath. This gives it protection against 7.62 mm small arms fire and small artillery shell fragments. It does not protect it against 12.7 mm or .50-caliber armor-piercing heavy machine gun fire or larger shell fragments. The torsion bar suspension consists of six evenly spaced large rubber-tired road wheels with

10044-629: The front. The early French Schneider CA1 mounted a short 75 mm gun in a sponson on the right hand side, while the Saint-Chamond mounted a standard 75 mm field gun in the nose. The thin armour of the tanks meant that such weapons were effective against other vehicles, though the Germans fielded few tanks anyway and the Allied tanks concentrated on anti-infantry and infantry support activities. This thinking remained pervasive into

10168-408: The gap between the breech face and the breech end of the barrel. PK barrels have a folding carry handle/grip that is positioned to the left of the receiver and is used to transport the weapon and quickly and safely change-out barrels to prevent barrel overheating. The bore is chrome-lined and features four right-hand grooves at a 240 mm (1 in 9.45 in) rifling twist rate. The muzzle is threaded for

10292-431: The gas cylinder into the atmosphere, thus varying the amount of energy transferred on to the long-stroke piston. The PK general-purpose machine gun U-shaped receiver is stamped from a smooth 1.5 mm (0.06 in) sheet of steel that is supported extensively by pins and rivets. For additional rigidity and strength the PK receiver features double walls made from 1.5 mm steel plates that are welded together with

10416-407: The gun's receiver. The 100-round belt "assault" box has a folding lid in its cover for feeding the ammunition belt when the box is attached under the machine gun receiver and weighs 3.9 kg (8.60 lb) or 3.4 kg (7.50 lb) for the modernised all aluminium lightweight variant. When the machine gun is fired from a bipod, the 100-round ammunition box is normally attached to the underside of

10540-454: The guns were almost exclusively rifled , but now most new tanks have smoothbore guns. Rifling in the barrel imparts spin on the projectile to stabilized it, improving ballistic accuracy. The best traditional antitank weapons have been kinetic energy rounds, whose penetrating power and accuracy is greatly decreased with the loss in muzzle velocity at extended range. For longer ranges high-explosive anti-tank rounds are more effective, but accuracy

10664-448: The hinge behind. The iron sight line has a 663  mm (26.1  in ) sight radius. Like the RPD rear sight, the PK rear sight also features full windage adjustment in the form of small dials on either side of the notch. The front sight assembly is mounted near the end of the barrel and consists of a protected open post adjustable for elevation in the field. PK machine guns that feature

10788-670: The improvements were instead made in ammunition and fire-control systems . With kinetic energy penetrator rounds, solid shot and armour-piercing shell gave way to armour-piercing discarding sabot ( APDS ) (a product of 1944), and fin-stabilized ( APFSDS ) rounds with tungsten or depleted uranium penetrators. Parallel developments brought rounds based on chemical energy; high-explosive squash head (HESH), and shaped-charge high-explosive anti-tank (HEAT), with penetrating power independent of muzzle velocity or range. Stadiametric range-finders were successively replaced by coincidence and laser rangefinders . Accuracy of modern tank guns

10912-481: The installation of various muzzle devices such as a flash hider . The muzzle was normally equipped with a conical flash suppressor that added 53 mm (2.1 in) to the barrel and later a long slotted flash suppressor that added 72 mm (2.8 in) to the barrel. Later when the PKM variant was introduced the PK series barrel fluting was omitted and the muzzle device was changed to a shorter cylindrical slotted flash suppressor that added 40 mm (1.6 in) to

11036-476: The iron sights. It weighs 0.8 kg, offers 4× magnification with a field of view of 8° and 35 mm eye relief. The 1P29 is issued with a canvas pouch, a lens cleaning cloth, combination tool, two rubber eyecups, two eyecup clamps and three different bullet drop compensation (BDC) cams for the AK-74 , RPK-74 and PK machine gun. The 1P29 is intended for quickly engaging point and area targets at various ranges. On

11160-542: The larger bore weapons were mounted within the tank hull while a second gun for use against tanks was fitted in a turret. However, other strategists saw new roles for tanks in war, and wanted more specifically developed guns tailored to these missions. The ability to destroy enemy tanks was foremost on their minds. To this end, the emerging anti-tank gun designs were modified to fit tanks. These weapons fired smaller shells, but at higher velocities with higher accuracy, improving their performance against armor. Such light guns as

11284-400: The last road wheels. The rear outlets have lids that can be fully or partially closed, redirecting the water stream to the forward-directed outlets at the sides of the hull, thus enabling the vehicle to turn or go in reverse. To turn to the left for example, the left water-jet is covered, to turn to the right, the right water-jet is covered. To make a 180° turn, one water-jet sucks in water while

11408-527: The late 1940s. The most successful was "объект 740" (Object 740) designed by the engineer N. Shashmurin working at the VNII-100 institute in Leningrad (a research institute of Chelyabinsk Tank Factory ChTZ) in 1949–1950, under an initial supervision of Josef Kotin from Kirov Plant . The vehicle was successful because it had a simple design, good navigational traits and a good cross country capability. At

11532-493: The latest Russian T-90 , Ukrainian T-84 , and Serbian M-84AS MBTs. The German company Rheinmetall developed a more conventional 120 mm smoothbore tank gun which can fire LAHAT missiles, adopted for the Leopard 2 , and later the U.S. M1 Abrams . The chief advantages of smoothbore designs are their greater suitability for fin stabilised ammunition and their greatly reduced barrel wear compared with rifled designs. Much of

11656-600: The left side of the receiver for mounting aiming optics. For heavier employment, the PKMS (ПКМ Станковый: "PKM Mounted") is mounted on the Stepanov 6T5 tripod mount. The PKM and 6T5 tripod weigh 12 kg (26.46 lb). The tripod mount, designed by L. V. Stepanov for the PKM machine gun entered service in 1969 and weighs 4.5 kg (9.92 lb). It is a lighter mount for the PK(M) general-purpose machine gun without affecting

11780-585: The middle of the PKB. Another configuration of the PKB has the normal stock and trigger mechanism removed and replaced by twin spade grips and a butterfly trigger. The PKT (ПК Танковый, "PK Tank") (1968) is a solenoid -fired coaxial version of PK to replace the SGMT Goryunov vehicle-mounted machine gun. Modifications include the removal of the stock, a longer (722 mm (28.4 in)) and heavier barrel that adds 30 m/s (98 ft/s) muzzle velocity,

11904-413: The modernised all aluminium lightweight variant. Both metal ammunition boxes have canvas carry handles. All openings on the machine gun, particularly the ejector port on the left and the belt feed entrance on the right, are covered with spring-loaded dust covers so that the openings are only exposed when they need to be. The PK is equipped with a simple detachable bipod mounted to the gas cylinder beneath

12028-534: The multi-model NSPU-3 ( 1PN51 ) night vision scope while the PKMN-2 can mount the multi-model NSPUM ( 1PN58 ) night vision scope. It can also be fitted with the 1PN93 series passive night sights. Besides the Shakhin and 1PN116 thermal sights and the 1PN119 anti-sniper special-purpose night vision sight are available for mounting on PK machine guns that like the PKMN model feature a Warsaw Pact side-rail bracket on

12152-511: The other pushes it out. This system was designed by N. Konowalow. It is the same system as the one used in the BTR-50 APC, which was based on the PT-76. The tank can swim at up to 10.2 km/h and has a range of 100 km. It can cross most water obstacles and can also swim in the sea. However, its amphibious design makes it disproportionally large for a vehicle of its weight and allows less armor protection than other light tanks. The PT-76

12276-404: The receiver cover or on the ammunition feed tray cover hinged under it. The PK feed mechanism pulls the rimmed 7.62×54mmR cartridges out from the back of the ammunition belt and drops the cartridges down into the feed way, allowing the bolt to strip and feed the cartridges into the chamber for firing. The PK feed mechanism is radically different from that of 7.62×51mm NATO machine guns based on

12400-769: The receiver for mounting aiming optics. Modernised version of the PKT. Modernised version of the PKB. In the early 1990s, as part of the preparations to join NATO, the Polish armed forces were looking for a replacement for the PK-series machine guns then in service. The H. Cegielski - Poznań S.A. Works in Poznań modified the PK/PKS to feed standard 7.62×51mm NATO cartridges and use NATO standard ammunition belts . The new model received

12524-454: The receiver. For the medium machine gun role, there is also a 200/250-round ammunition box made from an aluminium frame and steel cover available which can be mounted on the tripods used for the PK machine gun series. A 200/250-round ammunition box containing a 250-round non-disintegrating belt weighs 9.4 kg (20.72 lb) and containing a 200-round non-disintegrating belt weighs 8 kg (17.64 lb) or 6.2 kg (13.67 lb) for

12648-487: The reconnaissance subunits of tank divisions and mechanized divisions of the Red Army and Soviet marines divisions. Although it has been replaced in front line service by the BMP-1 , it may still be found in the reconnaissance companies and battalions of some motorized rifle and tank regiments and divisions, as well as in naval infantry units. Aside from its reconnaissance role, it is also used for crossing water obstacles in

12772-438: The right rear tripod leg in such a manner that the gun can be moved with the ammunition box still in place and with the gun loaded. This enables one crew member to carry and operate the gun in combat without having to unload the gun before repositioning the gun. The PKMSN (ПКМС Ночной: "PKMS Night-Vision") is a special model of the tripod-mounted variant (PKMS) that can mount night sights for low-visibility operations, similar to

12896-420: The right side of the field of view a stadiametric rangefinder is incorporated that can be used to determine the distance from a 1.5 meters (4 ft 11.1 in) tall object from 400 to 1,200 m (437 to 1,312 yd). The reticle is an inverted aiming post in the top half of the field of view and is tritium -illuminated for low-light condition aiming. A later designed similar optical sight suitable for

13020-475: The standard German panzer had either a 20 mm or 37 mm medium-velocity weapon, but by 1945 long-barrelled 75 mm and 88 mm high-velocity guns were common. The Soviets introduced their 122 mm in a turreted heavy tank series, the IS tanks . Shells were improved to provide better penetration with harder materials and scientific shaping. All of these meant improvements in accuracy and range, although

13144-435: The stock; the pressure was so great that one of the soldiers responsible for testing the PN1 broke his cheekbone. Based on the test results, the army preferred the Kalashnikov design. In 1961, the 7.62x54R mm Kalashnikov universal machine gun was adopted and put into production. The production of the PK/PKS took place at the Kovrov Mechanical Plant and used the tripod mount and an ammunition belt boxes originally designed for

13268-490: The tank , Tank classification , Tanks in the Cold War Tank gun A tank gun is the main armament of a tank . Modern tank guns are high-velocity, large-caliber artilleries capable of firing kinetic energy penetrators , high-explosive anti-tank , and cannon-launched guided projectiles . Anti-aircraft guns can also be mounted to tanks. As the tank's primary armament, they are almost always employed in

13392-405: The tank is afloat. It can swim after switching on the two electric bilge pumps, erecting the trim vane which improves the vehicle's stability and displacement in the water and prevents water from flooding into the bow of the tank. Switching the driver's periscope for a swimming periscope enables the driver to see over the trim vane. When not in use the trim vane is stowed in the front of the bow under

13516-574: The tank was equipped with new vision and communications devices. First series tanks were subsequently modified, receiving the D-56TM gun and new equipment. In 1959 an improved variant, the PT-76B, was adopted and remained in production until 1967 (main improvements were the D-56TS gun with stabilization and CBRN protection ). In 1964 the United States obtained a PT-76 by undisclosed means. The tank

13640-562: The time, its water-jet design was innovative. A prototype was built at Kirov Plant in 1950 and the tank was officially adopted on 6 August 1951 with the designation PT-76. Production started at the Stalingrad Tractor Factory (STZ). The tank was subsequently modified. In 1957, the D-56T gun was replaced with the D-56TM - with double-baffle muzzle brake and fume extractor - and the hull was raised by 13 cm; additionally

13764-405: The turret, the commander sits on the left side of the main gun and the loader sits on the right. They have a large oval shaped double hatch, which opens forwards on top of the turret. The driver sits in the center of the front of the hull and has a one piece hatch that opens to the right, with three vision blocks and periscopes located beneath the main gun at the top of the sloping glacis plate. Under

13888-643: The two TOW helicopters had destroyed 9 tanks and damaged one more. Four destroyed and one damaged were PT-76s. The PT-76 saw action with Indian forces in the Indo-Pakistani War of 1965 and 1971 . The tactics of the Indian Army enabled the PT-76 to play a vital role in the Eastern theater of the 1971 war where the PT-76s proved superior to the obsolete Pakistani M24 Chaffee light tanks despite being outnumbered. A good example of such an engagement

14012-429: The two in the center are for a drum type. These additional tanks increase the range from 370 to 400 km to 480–510 km. The PT-76 is a reliable, simple to operate and highly mobile reconnaissance vehicle and is ideally designed for amphibious operations, but it has many limitations as a fighting vehicle. The PT-76 is amphibious, it has a flat, boat-shaped hull which is hermetical and ensures minimal resistance when

14136-573: The underground bunkers. A few survivors broke out and were airlifted to safety. The first tank-to-tank engagement occurred in mid-1968 when a US reconnaissance airplane observed a PT-76 being washed by its crew in the Bến Hải River in the DMZ (17th Parallel). The Forward Air Control pilot radioed the tank's position to a nearby M48 Patton tank unit of the US 3rd Tank Battalion . With the FAC adjusting fire,

14260-574: The use of an unmanned turret in the T-14 Armata . In the 1960s, smoothbore tank guns were developed by the United States, the Soviet Union, and later by the experimental American-West German MBT-70 joint project. High-precision smoothbore tank gun barrels were perfected by the US Army's Weapons Laboratory at the Watervliet Arsenal based on a pair of patents by inventor Albert L. de Graffenried. More than 20,000 tank cannons were manufactured by

14384-465: The vehicle, including Afghanistan , Albania , Angola , China , Congo , Cuba , Egypt , Finland , Guinea , Hungary , India , Indonesia , Iraq , Laos , Madagascar , Mozambique , North Korea , Pakistan , Poland , North Vietnam , and Yugoslavia . The PT-76 was used as the standard reconnaissance tank of the Soviet Union and Warsaw Pact armies. It was also intended for water obstacle fording operations and naval infantry landings. It served in

14508-469: The war – a vehicle specifically designed for anti-tank work, and armed more heavily than a tank on the same chassis could be. They generally fell into three overlapping categories: improvised modifications of old or captured tanks to render them viable again (such as converting the machine-gun-only Panzer I into the Panzerjäger I ), often with haphazard, poorly protected, limited-traverse weapon mounts;

14632-463: The way around, and are linked by a coiling wire on each side. The links are made of 0.8 mm (0.03 in) thick high carbon stamped steel sheet metal that is zinc phosphated and varnished for protection. These belts are preloaded at ammunition factories in 25-round connectable belt lengths and can be linked to any length necessary. Factory connected PK ammunition belts are available in 25, 100, 200 and 250 rounds lengths. Typical of Soviet machine guns,

14756-580: Was against the Lang Vei Special Forces camp on 6/7 February 1968 (they had already been used in the preceding Battle of Ban Houei Sane , which was just across the border in Laos however). Thirteen PT-76s, of the PAVN 202nd Armored Regiment spearheaded an assault against approximately 24 Green Berets , 500 South Vietnamese irregulars and 350 Laotian Royal soldiers. The defenders fought back with their 106 mm M40 recoilless rifle (one at

14880-465: Was developed under the designation "V-6" by halving the "V-12"-engine from the T-54/55 . It develops 240 hp (179 kW) at 1,800 rpm which gives it a road speed of 44 km/h and a range of 370 km to 400 km. The vehicle can cross 1.1 m high vertical obstacles and 2.8 m wide trenches and climb 52° gradients. The engine has a cooling system and an initial heater (intended for use when

15004-466: Was earlier envisioned for the Nikitin-Sokoiov machine gun that was not adopted by the Soviet Union . All types of ammunition belt boxes are carried and mounted separately. The Rakov device is used for loading ammunition belts. The PK machine gun is attached to a cradle on the 6T2 Samozhenkov mount. The cradle is hinged to a plug-in swivel equipped with a rack-and-pinion traversing mechanism, and

15128-597: Was evaluated by the Tank-Automotive Center in February, and was deemed inferior to existing light American tanks. The PT-76 has a typical tank layout: the steering compartment at the front, the combat compartment in the center and the engine compartment at the back. The tank has a three-man crew, with the commander also acting as the radio operator and gunner. This reduces his effectiveness as an observer. The commander and loader stations are located inside

15252-409: Was fitted with a hinged butt-rest. The barrel fluting was omitted and the flash hider was changed. Later on the PKM was equipped with a new black glass-filled polyamide buttstock and pistol grip shaped like the previously used laminated wooden stock and grip. The PKMN (ПКМ Ночной: "PKM Night-Vision") is a variant that can mount a night sight for low-visibility operations. The PKMN-1 can thus mount

15376-575: Was the Battle of Garibpur , where an Indian Army Infantry Battalion with only 14 PT-76s was able to maul a much larger brigade -strength unit of Pakistani armor and inflict heavy casualties. During the battle 8 Pakistani M24 Chaffee tanks were destroyed, 3 captured at the cost of 2 PT-76. The PT-76 also saw service in the Six-Day War (1967) during which the Israeli army destroyed or captured

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