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55-531: It was designed by AR57 LLC. The AR-57 PDW upper is a new design on AR-15/M16 rifles, blending the AR-15/M16 lower with a lightweight, monolithic upper receiver system chambered in 5.7×28mm. This model is also sold as a complete rifle, supplied with two 50-round P90 magazines. The magazines mount horizontally on top of the front handguard, with brass ejecting through the magazine well. AR-15/M16-based STANAG magazines can be used to catch spent casings by taking out

110-468: A NATO request as a replacement for 9×19mm Parabellum submachine guns. The PDW is a compact automatic weapon that can defeat enemy body armor and which can be used conveniently by non-combatant and support troops, as well as a close quarters battle weapon for special forces and counter-terrorist groups. Introduced in 1991, the FN P90 features a bullpup design with a futuristic appearance. It has

165-436: A relative density of 1.44 (0.052 lb/in ). The polymer owes its high strength to the many inter-chain bonds. These inter-molecular hydrogen bonds form between the carbonyl groups and N H centers. Additional strength is derived from aromatic stacking interactions between adjacent strands. These interactions have a greater influence on Kevlar than the van der Waals interactions and chain length that typically influence

220-436: A $ 5 million grant to research the use of the fabric in bullet-proof vests. Kevlar 149 was invented by Jacob Lahijani of Dupont in the 1980s. Kevlar is synthesized in solution from the monomers 1,4- phenylene -di amine ( para -phenylenediamine ) and terephthaloyl chloride in a condensation reaction yielding hydrochloric acid as a byproduct. The result has liquid-crystalline behavior, and mechanical drawing orients

275-446: A 50-round magazine housed horizontally above the barrel, an integrated reflex sight and fully ambidextrous controls. A simple blow-back automatic weapon, it was designed to fire the FN 5.7×28mm cartridge which can penetrate soft body armor. The P90 was designed to have a length no greater than a man's shoulder width, to allow it to be easily carried and maneuvered in tight spaces, such as

330-453: A NATO CRISAT vest or an NIJ IIIA soft Kevlar armor at up to 200 m (220 yd)), PDWs have also been used by special forces , paramilitaries , heavily armed tactical police , and bodyguards . In the late 19th and early 20th centuries, shortened versions of the infantry rifle were issued as " carbines " for cavalry troops and gun crews. This designation was dropped as infantry rifle designs became shortened overall, such as in

385-599: A few examples kept by Ordnance Department . In 1918, Ribeyrolles, Sutter and Chauchat designed the Chauchat-Ribeyrolles 1918 submachine gun . This weapon was meant to be used for close-range protection for the French tank crews. The weapon is based on the RSC Mle. 1917 semi-automatic rifle mechanism. The first trials used a Mannlicher–Berthier clip holding eight cartridges. The trials continued until 1919 with

440-426: A key component in their construction. Other military uses include bulletproof face masks and spall liners used to protect the crews of armoured fighting vehicles . Nimitz -class aircraft carriers use Kevlar reinforcement in vital areas. Civilian applications include: high heat resistance uniforms worn by firefighters, body armour worn by police officers, security, and police tactical teams such as SWAT . Kevlar

495-489: A price range much higher than average cost of basketball shoes. It was also used in the laces for the Adidas F50 adiZero Prime football boot. Several companies, including Continental AG , manufacture cycle tires with Kevlar to protect against punctures. Folding-bead bicycle tires, introduced to cycling by Tom Ritchey in 1984, use Kevlar as a bead in place of steel for weight reduction and strength. A side effect of

550-606: A proprietary cartridge, such as the 5.7×28mm cartridge for the FN P90 or the 4.6×30mm for the H&;K MP7, neither of which were originally compatible with any existing pistols or rifles/carbines. Although both manufacturers planned handguns that used the same proprietary rounds, only FN went forward with production of the Five-SeveN pistol, which was the only handgun option available for the 5.7×28mm cartridge for over two decades until

605-592: A requirement for a "light rifle" with greater range, firepower, and accuracy than the M1911 pistol while weighing half as much as the M1 Garand. As a result, the U.S. developed the semi-automatic M1 Carbine and shortly thereafter the select-fire M2 Carbine. Widely employed until the end of the Vietnam War, these carbines are generally considered the forerunners of modern personal defense weapons. In 1969, AO-46

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660-737: A scaled-down intermediate cartridge , essentially making them an "in-between" hybrid between a submachine gun and a conventional carbine . The use of these rifle-like cartridges gives the PDWs much better ballistic performance ( effective range , external ballistics and armor-penetrating capability) than conventional submachine guns, which fire larger-caliber but slower and less aerodynamic handgun cartridges . The low recoil of these "sub-intermediate" cartridges also makes muzzle jumps on PDWs (which typically have short barrels ) much easier to handle than short-barreled rifles , especially when shooting in automatic fire or burst fire . The name describes

715-498: A weapon using the same magazine as the Chauchat. The results were satisfactory but the weapon was too powerful for the intended self-protection use. A mix of standard and tracer bullets was planned to be used to assist in aiming. In 1938, the U.S. Army Ordnance Department received a request for a light rifle to be issued to mortarmen, radiomen, drivers, clerks, cooks, and similar grades. During field exercises, these troops found that

770-527: Is a stub . You can help Misplaced Pages by expanding it . This article relating to submachine guns is a stub . You can help Misplaced Pages by expanding it . Personal defense weapon Personal defense weapons ( PDWs ) are a class of compact, magazine -fed automatic firearms that are typically submachine guns designed to fire rifle-like cartridges . Most PDWs fire a small-caliber (generally less than 8 mm or 0.31 in in bullet diameter), high-velocity centerfire bottleneck cartridge resembling

825-887: Is also found as a braid layer used on the outside of hose assemblies, to add protection against sharp objects. Some cellphones (including the Motorola RAZR Family , the Motorola Droid Maxx , OnePlus 2 and Pocophone F1 ) have a Kevlar backplate, chosen over other materials such as carbon fiber due to its resilience and lack of interference with signal transmission. The Kevlar fiber/epoxy matrix composite materials can be used in marine current turbines (MCT) or wind turbines due to their high specific strength and light weight compared to other fibers. Aramid fibers are widely used for reinforcing composite materials, often in combination with carbon fiber and glass fiber . The matrix for high performance composites

880-404: Is easy to use while having sufficient firepower to suppress enemy charges and hold them beyond a safe perimeter to prevent the defenders from being overrun, but the risk of hostility is rare enough that a standard service rifle would be an unnecessary burden during their normal duties. Because of their light weight, controllability, ease of operation and close-range effectiveness (can penetrate

935-422: Is five times stronger than steel. It is also used to make modern marching drumheads that withstand high impact; and for mooring lines and other underwater applications. A similar fiber called Twaron with the same chemical structure was developed by Akzo in the 1970s; commercial production started in 1986, and Twaron is manufactured by Teijin . Poly-paraphenylene terephthalamide (K29) – branded Kevlar –

990-409: Is slightly stronger at low temperatures. At higher temperatures the tensile strength is immediately reduced by about 10–20%, and after some hours the strength progressively reduces further. For example: enduring 160 °C (320 °F) for 500 hours, its strength is reduced by about 10%; and enduring 260 °C (500 °F) for 70 hours, its strength is reduced by about 50%. Kevlar is often used in

1045-440: Is used in rope and in cable, where the fibers are kept parallel within a polyethylene sleeve. The cables have been used in suspension bridges such as the bridge at Aberfeldy, Scotland . They have also been used to stabilize cracking concrete cooling towers by circumferential application followed by tensioning to close the cracks. Kevlar is widely used as a protective outer sheath for optical fiber cable , as its strength protects

1100-401: Is used to manufacture gloves, sleeves, jackets, chaps and other articles of clothing designed to protect users from cuts, abrasions and heat. Kevlar-based protective gear is often considerably lighter and thinner than equivalent gear made of more traditional materials. It is used for motorcycle safety clothing , especially in the areas featuring padding such as the shoulders and elbows. In

1155-421: Is usually epoxy resin . Typical applications include monocoque bodies for Formula 1 cars, helicopter rotor blades, tennis , table tennis , badminton and squash rackets , kayaks , cricket bats , and field hockey , ice hockey and lacrosse sticks. Kevlar 149, the strongest fiber and most crystalline in structure, is an alternative in certain parts of aircraft construction. The wing leading edge

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1210-499: Is usually a resin poured onto the Kevlar to make the head airtight, and a nylon top layer to provide a flat striking surface. This is one of the primary types of marching snare drum heads. Remo 's Falam Slam patch is made with Kevlar and is used to reinforce bass drum heads where the beater strikes. Kevlar is used in the woodwind reeds of Fibracell. The material of these reeds is a composite of aerospace materials designed to duplicate

1265-498: The M1 Garand rifle was too heavy and too cumbersome for general issue. And, while handguns are undeniably convenient, they had limited range, accuracy and power. This request was refused by authorities. In 1940, after Germany's use of glider-borne and paratroop forces to infiltrate and attack strategic points behind the front lines, the request for a light rifle was resubmitted and subsequently approved. U.S. Army Ordnance issued

1320-669: The M2 Bradley , named the M231 Firing Port Weapon . In 1980, the weapon was adopted as the M231. Although most of the Bradley AFV's ports have since been removed, these weapons are maintained, and are used by crews for self-defense, close-quarters situations, and for firing from the rear door firing ports as intended. Developed during the 1980s, the "Personal Defense Weapon" (PDW) concept was created in response to

1375-554: The NA48 experiment at CERN to separate a vacuum vessel from a vessel at nearly atmospheric pressure, both 192 cm (76 in) in diameter. The window has provided vacuum tightness combined with reasonably small amount of material (only 0.3% to 0.4% of radiation length ). Kevlar is a well-known component of personal armor such as combat helmets , ballistic face masks , and ballistic vests . The PASGT helmet and vest that were used by United States military forces used Kevlar as

1430-645: The Short Magazine Lee–Enfield rifle. Thereafter, handguns were typically issued as self-defense weapons. However, they were not effective in most close combat situations. As a result, during the First World War, the Mauser C96 and artillery versions of the Luger pistol were issued with attachable shoulder stock holsters, which allowed for greater control and accuracy. During World War I,

1485-587: The 7N21 and 7N31 ammunition. The Russian Aerospace Forces added the PPK-20 variant of the PP-19-01 Vityaz into the ejection survival kits of the MiG-29 , Mig-35 , Su-24 , Su-27 , Su-30SM , Su-34 , Su-35 and Su-57 . The PDW concept has not been widely successful, partly because existing PDWs are not significantly cheaper to manufacture than carbines or full-size military rifles. Most PDWs also use

1540-629: The United States secretly developed the Pedersen device attachment for the M1903 Springfield rifle that allowed it to fire the .30-18 Auto (7.65×20mm Longue) pistol cartridge in semi-automatic mode. This attachment was developed to allow an infantryman to convert "his rifle to a form of submachine gun or automatic rifle" in approximately 15 seconds. Production of the device and modified M1903 rifles started in 1918. However,

1595-596: The United States. The Heckler & Koch MP7 is also used in a number of countries, including Austria, France, Germany, Ireland, Norway, Malaysia, and the United Kingdom. 9×21mm IMI .357 SIG .40 S&W Italy PDW-caliber guns without select fire capabilities CMMG Resolute, Mk4/Mk57 5.7×28mm Kevlar Kevlar (para-aramid) is a strong, heat-resistant synthetic fiber , related to other aramids such as Nomex and Technora . Developed by Stephanie Kwolek at DuPont in 1965,

1650-400: The bow's user. To date, the only manufacturer of this type of bow is CodaBow . Kevlar is also presently used as a material for tailcords (a.k.a. tailpiece adjusters), which connect the tailpiece to the endpin of bowed string instruments. Kevlar is sometimes used as a material on marching snare drums. It allows for an extremely high amount of tension, resulting in a cleaner sound. There

1705-487: The cable from damage and kinking. When used in this application it is commonly known by the trademarked name Parafil. Kevlar was used by scientists at Georgia Institute of Technology as a base textile for an experiment in electricity-producing clothing. This was done by weaving zinc oxide nanowires into the fabric. If successful, the new fabric will generate about 80 milliwatts per square meter. A retractable roof of over 60,000 sq ft (5,600 m ) of Kevlar

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1760-437: The carcinogenic properties associated with asbestos. Wicks for fire dancing props are made of composite materials with Kevlar in them. Kevlar by itself does not absorb fuel very well, so it is blended with other materials such as fiberglass or cotton . Kevlar's high heat resistance allows the wicks to be reused many times. Kevlar is sometimes used as a substitute for Teflon in some non-stick frying pans. Kevlar fiber

1815-473: The core pierce it. The RG054 variant of the 9×21mm cartridge follows the same pattern. The space between the core and the bimetallic jacket is filled with polyethyelene which results in 7N21 being lighter than regular 9×19mm, 7N31 is even lighter than 7N21. Using a different variant of the same cartridge bears the advantage that regular ammunition can still be used. The PP-19-01 Vityaz , PP-2000 and GSh-18 can use regular 9×19mm Parabellum as well as

1870-594: The feed lips, spring and follower. Sheet metal brass catchers can also be used on the AR-15/M16 lower. Various scopes and other accessories can be mounted on the picatinny rail. Unlike the standard AR-15 configuration which uses a gas-tube system, the AR-57 cycles via straight blowback . A fully automatic version exists and was marketed as a competitor to the P90 and other personal defense weapons . Suppressed versions are also available. This article relating to rifles

1925-438: The field of cryogenics for its low thermal conductivity and high strength relative to other materials for suspension purposes. It is most often used to suspend a paramagnetic salt enclosure from a superconducting magnet mandrel in order to minimize any heat leaks to the paramagnetic material. It is also used as a thermal standoff or structural support where low heat leaks are desired. A thin Kevlar window has been used by

1980-527: The first time. It launched the Elite II Series, with enhancements to its earlier version of basketball shoes by using Kevlar in the anterior as well as the shoe laces . This was done to decrease the elasticity of the tip of the shoe in contrast to the nylon conventionally used, as Kevlar expanded by about 1% against nylon which expanded by about 30%. Shoes in this range included LeBron, HyperDunk and Zoom Kobe VII. However these shoes were launched at

2035-583: The folding bead is a reduction in shelf and floor space needed to display cycle tires in a retail environment, as they are folded and placed in small boxes. Kevlar has also been found to have useful acoustic properties for loudspeaker cones, specifically for bass and mid range drive units. Additionally, Kevlar has been used as a strength member in fiber optic cables such as the ones used for audio data transmissions. Kevlar can be used as an acoustic core on bows for string instruments . Kevlar's physical properties provide strength, flexibility, and stability for

2090-518: The heavy use of polymers in its construction, the MP7 is much lighter than older SMG designs, weighing only 1.2 kg (2.65 lb) with an empty 20-round magazine. Russia uses 7N21 and 7N31 cartridges which are hotter loaded 9x19mm Parabellum cartridges with special armor piercing bullets. The armor piercing bullets consist of a hardened steel core inside a lighter sleeve which damages soft targets but strips off if it hits an armored target and lets

2145-429: The high-strength material was first used commercially in the early 1970s as a replacement for steel in racing tires. It is typically spun into ropes or fabric sheets that can be used as such, or as an ingredient in composite material components. Kevlar has many applications, ranging from bicycle tires and racing sails to bulletproof vests , all due to its high tensile strength-to-weight ratio ; by this measure it

2200-411: The idea developed: "We folded it over a couple of times and shot at it. The bullets didn't go through." In tests, they strapped Kevlar onto anesthetized goats and shot at their hearts, spinal cords, livers and lungs. They monitored the goats' heart rate and blood gas levels to check for lung injuries. After 24 hours, one goat died and the others had wounds that were not life threatening. Shubin received

2255-522: The inside of an armored vehicle. Introduced in 2001, the Heckler & Koch MP7 is a direct rival to the FN P90. Featuring a more conventional-looking design, the MP7 uses a short-stroke piston gas system as used on H&K's G36 and HK416 assault rifles, in place of a blowback system traditionally seen on submachine guns. The MP7 is able to use 20-, 30- and 40-round magazines and fires 4.6×30mm ammunition which can penetrate soft body armor. Due to

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2310-592: The introduction of Ruger-57 in 2019. In turn, this made the PDW cartridges expensive to consumers due to the lack of mass production. Though personal defense weapons have not been very popular for their intended application, they have been acquired by various military special forces units and law enforcement groups, as an upgrade for their older submachine guns . The FN P90 and Five-seven pistol are used by military and police forces in over 40 countries, including Canada, Cyprus, France, Greece, India, Peru, Poland, Spain, and

2365-486: The more expensive hemp . It is one of the main materials used for paraglider suspension lines. It is used as an inner lining for some bicycle tires to prevent punctures. In table tennis , plies of Kevlar are added to custom ply blades, or paddles, in order to increase bounce and reduce weight. Tennis racquets are sometimes strung with Kevlar. It is used in sails for high performance racing boats. In 2013, with advancements in technology, Nike used Kevlar in shoes for

2420-473: The polymer chains in the fiber's direction. Hexamethylphosphoramide (HMPA) was the solvent initially used for the polymerization , but for safety reasons, DuPont replaced it by a solution of N -methyl-pyrrolidone and calcium chloride. As this process had been patented by Akzo (see above) in the production of Twaron , a patent war ensued. Kevlar production is expensive because of the difficulties arising from using concentrated sulfuric acid , needed to keep

2475-547: The properties of other synthetic polymers and fibers such as ultra-high-molecular-weight polyethylene . The presence of salts and certain other impurities, especially calcium , could interfere with the strand interactions and care is taken to avoid inclusion in its production. Kevlar's structure consists of relatively rigid molecules which tend to form mostly planar sheet-like structures rather like silk protein. Kevlar maintains its strength and resilience down to cryogenic temperatures (−196 °C (−320.8 °F)): in fact, it

2530-466: The sport of fencing it is used in the protective jackets, breeches, plastrons and the bib of the masks. It is increasingly being used in the peto , the padded covering which protects the picadors ' horses in the bullring. Speed skaters also frequently wear an under-layer of Kevlar fabric to prevent potential wounds from skates in the event of a fall or collision. In kyudo , or Japanese archery , it may be used for bow strings , as an alternative to

2585-451: The war ended before they were sent to Europe. The contract was cancelled on March 1, 1919, after production of 65,000 devices, 1.6 million magazines, 65 million cartridges and 101,775 modified Springfield rifles. The Pedersen device was declared surplus in 1931. To prevent them from falling into the hands of the lawless, nearly all of the stored devices were destroyed by the Army except for

2640-425: The water-insoluble polymer in solution during its synthesis and spinning . Several grades of Kevlar are available: The ultraviolet component of sunlight degrades and decomposes Kevlar, a problem known as UV degradation , and so it is rarely used outdoors without protection against sunlight. When Kevlar is spun , the resulting fiber has a tensile strength of about 3,620 MPa (525,000 psi) , and

2695-492: The way nature constructs cane reed. Very stiff but sound absorbing Kevlar fibers are suspended in a lightweight resin formulation. Kevlar is sometimes used in structural components of cars, especially high-value performance cars such as the Ferrari F40 . The chopped fiber has been used as a replacement for asbestos in brake pads . Aramids such as Kevlar release less airborne fibres than asbestos brakes and do not have

2750-630: The weapon's original conceptual role: as a compact but powerful small arm that can be conveniently carried for personal defense, usually by support personnel behind the front line such as military engineers , logistic drivers, medical specialists , artillery crews, or signallers . These "second-line" personnel are not strictly combat troops expected to directly engage the enemy, but may still be at risk of encountering decently equipped (and often well-armored) hostile skirmishers and infiltrators , therefore having to defend themselves in close quarters . Such encounters will warrant an effective weapon that

2805-438: Was "cloudy, opalescent upon being stirred, and of low viscosity " and usually was thrown away. However, Kwolek persuaded the technician, Charles Smullen, who ran the spinneret , to test her solution, and was amazed to find that the fiber did not break, unlike nylon . Her supervisor and her laboratory director understood the significance of her discovery and a new field of polymer chemistry quickly arose. By 1971, modern Kevlar

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2860-530: Was a key part of the design of the Olympic Stadium, Montreal for the 1976 Summer Olympics . It was spectacularly unsuccessful, as it was completed 10 years late and replaced just 10 years later in May 1998 after a series of problems. Kevlar can be found as a reinforcing layer in rubber bellows expansion joints and rubber hoses , for use in high temperature applications, and for its high strength. It

2915-696: Was an unsolicited design by Peter Andreevich Tkachev working at TsNIITochMash . Although not accepted for service, this design, in combination with report of the US use of the XM-177 in Vietnam led the GRAU to start the competition known as Project Modern , which led to the adoption of AKS-74U for service. In 1979, Rock Island Arsenal designed a version of the M16 assault rifle adapted for shooting from firing ports on

2970-583: Was introduced. However, Kwolek was not very involved in developing the applications of Kevlar. In 1971, Lester Shubin , who was then the Director of Science and Technology for the National Institute for Law Enforcement and Criminal Justice, suggested using Kevlar to replace nylon in bullet-proof vests. Prior to the introduction of Kevlar, flak jackets made of nylon had provided much more limited protection to users. Shubin later recalled how

3025-488: Was invented by the Polish-American chemist Stephanie Kwolek while working for DuPont, in anticipation of a gasoline shortage. In 1964, her group began searching for a new lightweight strong fiber to use for light, but strong, tires. The polymers she had been working with, poly-p-phenylene-terephthalate and polybenzamide, formed liquid crystals in solution, something unique to polymers at the time. The solution

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