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Colt ACR | |
---|---|
Colt ACR/M16A2E2 (centre) | |
Type | Assault rifle |
Place of origin | United States |
Production history | |
Designer | Colt's Manufacturing Company |
Designed | 1982 |
Manufacturer | Colt's Manufacturing Company |
Specifications | |
Mass | 3.306 kg (7.29 lb) without magazine and sight |
Length | 1,031 mm (40.6 in) (Stock extended) 933 mm (36.7 in) (Stock retracted) |
Cartridge | 5.56×45mm M855 or Duplex |
Action | Gas-operated, rotating bolt (direct impingement) |
Muzzle velocity | 948 m/s (3,110 ft/s) (M855) 884 m/s (2,900 ft/s) (Duplex) |
Effective firing range | 325 m (355 yd) (Duplex Ammunition) |
Feed system | 30-round detachable box magazine |
Sights | ×3.5 telescope or interchangeable iron sight |
The Colt ACR was Colt's entry in the U.S. DoD Advanced Combat Rifle program, which concluded with the result that none of the entrants achieved enough of an improvement over the M16 to be worth the cost.
The Colt ACR was not a total loss, however; the scope went on to be offered by Elcan, a version of which was eventually adopted as the M145 Machine Gun Optic used on a number of firearms, especially those from Diemaco (now Colt Canada).
The main differences of the Colt ACR and the M16A2 is the distinctive furniture. The handguard included a heat-resistant inner lining, vent holes for lightening and air cooling with a thickened ring around the front end to act as a handstop. This was topped with an elevated sight track rib with a white stripe to improve fast target acquisition. The pistol grip was longer and of a different profile than a traditional M16A2, and the rifle featured amibdexterous fire control selectors, removable scope and a streamlined 6 position telescopic stock. Lastly the rifle featured a flash-hider and a Muzzle Brake Compensator (MBC) designed to reduce recoil and compensate for muzzle climb. [1] [2]
Internally, an oil spring buffer was added to the lower receiver to control the cyclic rate and help reduce felt recoil. Combined with the MBC, these changes reduced felt recoil by 40 per cent compared to a standard M16A2.
The key design change was the use of "duplex rounds", a single cartridge with two bullets in it. Olin Corporation produced three different rounds for testing, the first consisting of two tungsten projectiles in a long-necked case, the second used a standard-length case with two 1.7 grams (27 gr), 4.0-millimetre (0.158 in) tungsten projectiles, and the final entry was another standard-length case with two 5.7-millimetre (0.224 in) projectiles, one 2.3 grams (35 gr) the other 2.1 g (33 gr). The latter was eventually selected for submission to the ACR trials. The basic idea of the duplex load is to increase the number of projectiles fired, which is the primary determinant of battlefield casualties. [3] However, they significantly reduced accuracy, leading to a maximum effective range of 325 m (1,066 ft) and requiring the user to also carry traditional ammunition for long-range shots. [2]
A muzzle brake or recoil compensator is a device connected to, or a feature integral to the construction of, the muzzle or barrel of a firearm or cannon that is intended to redirect a portion of propellant gases to counter recoil and unwanted muzzle rise. Barrels with an integral muzzle brake are often said to be ported. The concept of a muzzle brake was first introduced for artillery and was a common feature on many anti-tank guns, especially those mounted on tanks, in order to reduce the area needed to take up the strokes of recoil and kickback. They have been used in various forms for rifles and pistols to help control recoil and the rising of the barrel that normally occurs after firing. They are used on pistols for practical pistol competitions, and are usually called compensators in this context.
The Heckler & Koch G11 is a non-production prototype assault rifle developed during the late 1960s, 1970s and 1980s by Gesellschaft für Hülsenlose Gewehrsysteme (GSHG), a conglomeration of companies headed by firearm manufacturer Heckler & Koch, Dynamit Nobel, and Hensoldt Wetzlar. The rifle is noted for its use of caseless ammunition.
A smoothbore weapon is one that has a barrel without rifling. Smoothbores range from handheld firearms to powerful tank guns and large artillery mortars.
The .38 Super, also known as .38 Superauto, .38 Super Auto, or 9x23mmSR, is a pistol cartridge that fires a 0.356-inch-diameter (9.04 mm) bullet. It was introduced in the late 1920s as a higher pressure loading of the .38 ACP, also known as .38 Auto. The older .38 ACP cartridge propells a 130-grain (8.4 g) bullet at 1,050 ft/s (320.0 m/s), whereas the .38 Super pushes the same bullet at 1,280 ft/s (390.1 m/s). The .38 Super has gained distinction as the caliber of choice for many top practical shooting competitors; it remains one of the dominant calibers in IPSC competition.
The .338 Lapua Magnum is a rimless, bottlenecked, centerfire rifle cartridge. It was developed during the 1980s as a high-powered, long-range cartridge for military snipers. It was used in the War in Afghanistan and the Iraq War. As a result of this, it became more widely available. The loaded cartridge is 14.93 mm (0.588 in) in diameter (rim) and 93.5 mm (3.68 in) long. It can penetrate better-than-standard military body armor at ranges up to 1,000 metres (1,090 yd) and has a maximum effective range of about 1,750 metres (1,910 yd) with C.I.P. conform ammunition at sea level conditions. Muzzle velocity is dependent on barrel length, seating depth, and powder charge, and varies from 880 to 915 m/s for commercial loads with 16.2-gram (250 gr) bullets, which corresponds to about 6,525 J (4,813 ft⋅lbf) of muzzle energy.
The .22 Long Rifle or simply .22 LR is a long-established variety of .22 caliber rimfire ammunition originating from the United States. It is used in a wide range of rifles, pistols, revolvers, smoothbore shotguns, and submachine guns.
The Special Purpose Individual Weapon (SPIW) was a long-running United States Army program to develop, in part, a workable flechette-firing "rifle", though other concepts were also involved. The concepts continued to be tested under the Future Rifle Program and again in the 1980s under the Advanced Combat Rifle program, but neither program resulted in a system useful enough to warrant replacing the M16.
Transitional ballistics, also known as intermediate ballistics, is the study of a projectile's behavior from the time it leaves the muzzle until the pressure behind the projectile is equalized, so it lies between internal ballistics and external ballistics.
The 7×57mm Mauser is a first-generation smokeless powder rimless bottlenecked rifle cartridge. It is known as .275 Rigby in the United Kingdom. It was developed by Paul Mauser of the Mauser company in 1892 and adopted as a military cartridge by Spain in 1893. It was subsequently adopted by several other countries as the standard military cartridge, and although now obsolete as a military cartridge, it remains in widespread international use as a sporting round. Many sporting rifles in this calibre were made by British riflemakers, among whom John Rigby was prominent; and, catering for the British preference for calibres to be designated in inches, Rigby called this chambering the .275 bore after the measurement of a 7 mm rifle's bore across the lands.
The 6.8mm Remington Special Purpose Cartridge is a rimless bottlenecked intermediate rifle cartridge that was developed by Remington Arms in collaboration with members of the U.S. Army Marksmanship Unit, United States Special Operations Command to possibly replace the 5.56 NATO cartridge in a Short Barreled Rifle(SBR)/Carbine.
The Advanced Combat Rifle (ACR) was a United States Army program, started in 1986, to find a replacement for the M16 assault rifle. Under the stress of battle the average soldier with an M16 may shoot a target at 45 meters, but hit probability is reduced to one out of ten shots on target by 220 meters. Because of this, the ACR program was initiated in the late 1980s to create a weapon that could double the hit probability. The ACR program was preceded by older programs such as the Special Purpose Individual Weapon. The program ended in 1990 after an expenditure of approximately US$300 million.
The 5.45×39mm cartridge is a rimless bottlenecked intermediate cartridge. It was introduced into service in 1974 by the Soviet Union for use with the new AK-74. The 5.45×39mm gradually supplemented, then largely replaced the 7.62×39mm cartridge in Soviet and Warsaw Pact service as the primary military service rifle cartridge.
The 7.92×57mm Mauser is a rimless bottlenecked rifle cartridge. The 8mm Mauser cartridge was adopted by the German Empire in 1903–1905, and was the German service cartridge in both World Wars. In its day, the 8mm Mauser cartridge was one of the world's most popular military cartridges. In the 21st century it is still a popular sport and hunting cartridge that is factory-produced in Europe and the United States.
The .300 Winchester Magnum (7.62×67mmB) is a belted, bottlenecked magnum rifle cartridge that was introduced by Winchester Repeating Arms Company in 1963. The .300 Winchester Magnum is a magnum cartridge designed to fit in a standard rifle action. It is based on the .375 H&H Magnum, which has been blown out, shortened, and necked down to accept a .30 caliber (7.62 mm) bullet.
The 5.8×42mm / DBP87 is a military rimless bottlenecked intermediate cartridge developed in the People's Republic of China. There is limited information on this cartridge, although the People's Liberation Army says that it is superior to the 5.56×45mm NATO and Soviet 5.45×39mm cartridges. Another variant called the DBP88 "heavy round" was designed specifically for squad automatic weapons and designated marksman rifles. The 5.8×42mm "heavy round" cartridge has the same dimensions as the standard 5.8×42mm cartridge, but utilizes a longer streamlined bullet with a heavy steel core for increased performance at extended ranges and penetration. As of 2010 all 5.8×42mm cartridge variants have been succeeded by the DBP10 variant.
The 9.3×64mm Brenneke is a rimless bottlenecked centerfire rifle cartridge designed in 1927 by German gunmaker Wilhelm Brenneke. It is suitable for hunting medium to large game animals in Africa, Europe, and North America.
The high-low system, also referred to as the high-low pressure system, the high-low propulsion system, and the high-low projection system", is a design of cannon and anti-tank launcher using a smaller high-pressure chamber for storing the propellant. It enables a much larger projectile to be launched without the heavy equipment typically required for large caliber weapons. When the propellant is ignited, the higher pressure gases are bled out through vents at reduced pressure to a much larger low pressure chamber to push the projectile forward. The high-low system allows the weight of the weapon and its ammunition to be significantly reduced. Manufacturing cost and production time are drastically lower than for standard cannon or other small-arm weapon systems firing a projectile of the same size and weight. It has a far more efficient use of the propellant, unlike earlier recoilless weapons, where most of the propellant is expended to the rear of the weapon to counter the recoil of the projectile being fired.
The .276 Enfield (7×60mm) was an experimental rebated rim bottlenecked centerfire military rifle cartridge developed in conjunction with the Pattern 1913 Enfield (P'13) rifle. Development was discontinued by the onset of World War I.
The 7.62×51mm NATO is a rimless bottlenecked rifle cartridge developed in the 1950s as a standard for small arms among NATO countries. It is sometimes confused with the similarly named Russian 7.62×54mmR cartridge, a slightly longer, rimmed cartridge.
The AAI ACR was a prototype flechette-firing assault rifle built for the US Army's Advanced Combat Rifle program of 1989/90. Although the AAI design proved effective, as did most of the weapons submitted, the entire ACR program ended with none of the entrants achieving performance 100% better than the M16A2, the baseline for a successful ACR weapon.