Heckler & Koch MP5

MP5
Type	Submachine gun
Place of origin	West Germany
Service history
In service	1966–present
Used by	See Users
Production history
Designer	Tilo Möller, Manfred Guhring, Georg Seidl, Helmut Baureuter
Designed	1964–1966
Manufacturer	Heckler & Koch
Produced	1966–present
Variants	See Variants
Specifications
Weight	2.54 kg (5.6 lb) (MP5A2, MP5A4) 3.08 kg (6.8 lb) (MP5A3, MP5A5) 2 kg (4.4 lb) (MP5K, MP5KA1, MP5KA4, MP5KA5) 2.78 kg (6.1 lb) (MP5K-PDW) 2.80 kg (6.2 lb) (MP5SD1, MP5SD4) 3.10 kg (6.8 lb) (MP5SD2, MP5SD5) 3.60 kg (7.9 lb) (MP5SD3, MP5SD6) 2.67 kg (5.9 lb) fixed stock / 2.85 kg (6.3 lb) retractable stock (MP5/10) 2.67 kg (5.9 lb) fixed stock / 2.85 kg (6.3 lb) retractable stock (MP5/40)
Length	Fixed stock: 680 mm (26.8 in) (MP5A2, MP5A4, MP5/10, MP5/40) 790 mm (31.1 in) (MP5SD2, MP5SD5) Telescoping stock: 700 mm (27.6 in) stock extended / 550 mm (21.7 in) stock collapsed (MP5A3, MP5A5) 603 mm (23.7 in) stock extended / 368 mm (14.5 in) stock folded (MP5K-PDW) 805 mm (31.7 in) stock extended / 670 mm (26.4 in) stock collapsed (MP5SD3, MP5SD6) 660 mm (26.0 in) stock extended / 490 mm (19.3 in) stock collapsed (MP5/10, MP5/40) Receiver end cap: 325 mm (12.8 in) (MP5K, MP5KA1, MP5KA4, MP5KA5) 349 mm (13.7 in) (MP5K-PDW) 550 mm (21.7 in) (MP5SD1, MP5SD4)
Barrel length	225 mm (8.9 in) (MP5A2, MP5A3, MP5A4, MP5A5, MP5/10, MP5/40) 115 mm (4.5 in) (MP5K, MP5KA1, MP5KA4, MP5KA5) 140 mm (5.5 in) (MP5K-PDW) 146 mm (5.7 in) (MP5SD1, MP5SD2, MP5SD3, MP5SD4, MP5SD5, MP5SD6)
Width	50 mm (2.0 in) (MP5A2, MP5A3, MP5A4, MP5A5, MP5K, MP5KA1, MP5KA4, MP5KA5, MP5K-PDW, MP5/10, MP5/40) 60 mm (2.4 in) (MP5SD1, MP5SD2, MP5SD3, MP5SD4, MP5SD5, MP5SD6)
Height	260 mm (10.2 in) (MP5A2, MP5A3, MP5A4, MP5A5, MP5SD1, MP5SD2, MP5SD3, MP5SD4, MP5SD5, MP5SD6, MP5/10, MP5/40) 210 mm (8.3 in) (MP5K, MP5KA1, MP5KA4, MP5KA5, MP5K-PDW)
Cartridge	9x19mm Parabellum 10mm Auto (MP5/10) .40 S&W (MP5/40)
Action	Roller-delayed blowback, closed bolt
Rate of fire	700 rounds/min (MP5SD series), 800 rounds/min (MP5A series, MP5/10 and MP5/40), 900 rounds/min (MP5K series)
Muzzle velocity	400 m/s (1,312 ft/s) (MP5A2, MP5A3, MP5A4, MP5A5) 375 m/s (1,230.3 ft/s) (MP5K, MP5KA1, MP5KA4, MP5KA5, MP5K-PDW) 285 m/s (935.0 ft/s) (MP5SD1, MP5SD2, MP5SD3, MP5SD4, MP5SD5, MP5SD6) 425 m/s (1,394.4 ft/s) (MP5/10) 315 m/s (1,033.5 ft/s) (MP5/40)
Feed system	15- or 30- or 32- round detachable box magazine, 100-round Beta C-Mag drum magazine
Sights	Iron sights. Rear: rotary drum; front: hooded post

 

Heckler & Koch MP5

The Heckler & Koch MP5 (From Maschinenpistole 5 - German: "machine pistol model 5") is a 9mm submachine gun of German design, developed in the 1960s by a team of engineers from the German small arms manufacturer Heckler & Koch GmbH (H&K) of Oberndorf am Neckar.
The MP5 is currently one of the most widely used submachine guns in the world,^[1] having been adopted by numerous law enforcement agencies and special forces groups. In the 1990s, Heckler & Koch developed the Heckler & Koch UMP, the MP5's successor, though both remain in production.^[2]

History

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A SEAL Team 8 member armed with an MP5-N variant.

Heckler & Koch, encouraged by the success of the G3 automatic rifle, developed a family of small arms consisting of four types of firearms (all based on a common G3 design layout and operating principle), where the first type was chambered in 7.62x51mm NATO, the second—using the 7.62x39mm M43 round, third—the intermediate 5.56x45mm NATO caliber and the fourth type—chambering the 9x19mm Parabellum pistol cartridge. The MP5 was created within the fourth group of firearms and was initially known as the HK54.
Work on the MP5 began in 1964 and scarcely two years later it was adopted by the German Federal Police, border guard and army special forces.
The MP5 is manufactured under license in several nations including Greece (formerly at EBO - Hellenic Arms Industry, currently at EAS - Hellenic Defense Systems), Iran (Defense Industries Organization), Mexico (SEDENA), Pakistan (Pakistan Ordnance Factories), Saudi Arabia, Sudan (Military Industry Corporation), Turkey (MKEK), and the United Kingdom (initially at Royal Ordnance, later diverted to Heckler & Koch Great Britain).^[3]

[edit] Design details

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The primary version of the MP5 family is the MP5A2, which is a lightweight, air-cooled, selective fire delayed blowback operated 9x19mm Parabellum weapon with a roller-delayed bolt. It fires from a closed bolt (bolt forward) position.
The fixed, free floating, cold hammer-forged barrel has 6 right-hand grooves with a 1 in 250 mm (1:10 in) rifling twist rate and is pressed and pinned into the receiver.

[edit] Features

The first MP5 models used a double-column straight box magazine, but since 1977, slightly curved, steel magazines are used with a 15-round capacity (weighing 0.12 kg) or a 30-round capacity (0.17 kg empty).

A view through the weapon's aperture sight.

The sighting arrangement on the MP5 takes advantage of the natural ability of the eye and brain to easily align concentric circles (circles all having a common center). The mechanically adjustable iron sights (closed type) consist of a rotating rear diopter drum and a front post installed in a hooded ring. The rear sight is adjustable for both windage and elevation with the use of a special tool; the drum provides four different apertures of varying width used for firing at 25, 50, 75 and 100 m. However, adjusting the rear drum does not change the elevation or bullet strike of the rounds since the MP5 uses pistol cartridges, which share a similar point of impact between 25 and 100 m when zeroed at 25 m.
The MP5 has a hammer firing mechanism. The trigger group is housed inside an interchangeable polymer trigger module (with an integrated pistol grip) and equipped with a 3-position fire mode selector that serves as the manual safety toggle. The “S” or Sicher position in white denotes weapon safe, “E” or Einzelfeuer in red represents single fire, and “F” or Feuerstoß (also marked in red) designates continuous fire. The SEF symbols appear on both sides of the plastic trigger group. The selector lever is actuated with the thumb of the shooting hand and is located only on the left side of the original SEF trigger group or on both sides of the ambidextrous trigger groups. The safety/selector is rotated into the various firing settings or safety position by depressing the tail end of the lever. Tactile clicks (stops) are present at each position to provide a positive stop and prevent inadvertent rotation. The "safe" setting disables the trigger by blocking the hammer release with a solid section of the safety axle located inside the trigger housing.
The non-reciprocating cocking handle is located above the handguard and protrudes from the cocking handle tube at approx. a 45° angle. This rigid control is attached to a tubular piece within the cocking lever housing called the cocking lever support, which in turn, makes contact with the forward extension of the bolt group. It is not however connected to the bolt carrier and therefore cannot be used as a forward assist to fully seat the bolt group. The cocking handle is held in a forward position by a spring detent located in the front end of the cocking lever support which engages in the cocking lever housing. The lever is locked back by pulling it fully to the rear and rotating it slightly clockwise where it can be hooked into an indent in the cocking lever tube.

[edit] Operating mechanism

The bolt rigidly engages the barrel extension – a cylindrical component welded to the receiver that the barrel is pinned into. The delay mechanism is of the same design as that used in the G3 rifle. The two-part bolt consists of a bolt head with rollers and a bolt carrier. The heavier bolt carrier lies up against the bolt head when the weapon is ready to fire and inclined planes on the front locking piece lie between the rollers and force them out into recesses in the barrel extension.^[4]

The roller-delayed blowback mechanism originated from the aborted StG 45(M) assault rifle prototypes developed in Nazi Germany at the end of World War II.

When fired, expanding propellant gases produced from the burning powder in the cartridge exert rearward pressure on the bolt head transferred through the base of the cartridge case as it is propelled out of the chamber. A portion of these forces is transmitted through the rollers projecting from the bolt head, which are cammed inward against the inclined flanks of the locking recesses in the barrel extension and to the angled shoulders of the locking piece. The selected angles of the recesses and the incline on the locking piece produce a velocity ratio of about 4:1 between the bolt carrier and the bolt head. This results in a calculated delay, allowing the projectile to exit the barrel and gas pressure to drop to a safe level before the case is extracted from the chamber.

A British police officer guarding Downing Street with an MP5SFA3 semi-automatic carbine fitted with an underbarrel torch and an EOtech holographic sight.

The delay results from the amount of time it takes for enough recoil energy to be transferred through to the bolt carrier in a sufficient quantity for it to be driven to the rear against the force of inertia of the bolt carrier and the forward pressure exerted against the bolt by the recoil spring. As the rollers are forced inward they displace the locking piece and propel the bolt carrier to the rear. The bolt carrier's rearward velocity is four times that of the bolt head since the cartridge remains in the chamber for a short period of time during the initial recoil impulse. After the bolt carrier has traveled rearward 4 mm, the locking piece is withdrawn fully from the bolt head and the rollers are compressed into the bolt head. Only once the locking rollers are fully cammed into the bolt head can the entire bolt group continue its rearward movement in the receiver, breaking the seal in the chamber and continuing the feeding cycle.
Since the 9x19mm Parabellum cartridge is relatively low powered, the bolt does not have an anti-bounce device like the G3, but instead the bolt carrier contains tungsten granules that prevent the bolt group from bouncing back after impacting the barrel extension. The weapon has a fluted chamber that enhances extraction reliability by bleeding gases backwards into the shallow flutes running along the length of the chamber to prevent the cartridge case from expanding and sticking to the chamber walls (since the bolt is opened under relatively high barrel pressure). A spring extractor is installed inside the bolt head and holds the case securely until it strikes the ejector arm and is thrown out of the ejection port to the right of the receiver. The lever-type ejector is located inside the trigger housing (activated by the movement of the recoiling bolt).

[edit] Accessories

Three lugs are provided at the muzzle that are used to work with certain muzzle devices made by Heckler & Koch, including: a slotted flash suppressor, blank firing attachment (marked with a red painted band denoting use with blank ammunition only), an adaptor for launching rifle grenades (for use with rifle-style grenades with an inside diameter of 22 mm using a special grenade launching cartridge) and a cup-type attachment used to launch tear gas grenades.
The receiver housing has notches that permit the attachment of a standard Heckler & Koch quick-detachable scope mount (also used with the G3, HK33 and G3SG/1) that can be used to mount daytime optical sights (telescopic 4x24), night sights or a halogen flashlight. It can be used with reflex sights and laser pointers. The mount features two spring-actuated bolts, positioned along the base of the mount, which exert pressure on the receiver to hold the mount in the same position at all times assuring zero retention. All versions of the quick-detachable scope mount provide a sighting tunnel through the mount so that the shooter can continue to use the fixed iron sights with the scope mount attached to the top of the receiver.

[edit] Variants

The Heckler & Koch MP5 submachine gun is widely used by law enforcement, tactical teams and military forces. Seen here is the MP5A3 variant with the early 'slimline' handguard.

The MP5A2 has a fixed stock (made of a synthetic polymer), whereas the compact MP5A3 has a retractable metal stock.
In the early 1970s HK introduced a conversion kit for the MP5 that enables it to use sporting ammunition (.22 LR). This unit consists of a barrel insert, a bolt group and two 20-round magazines. This modification reduces the cyclic rate to 650 rounds/min.
The MP5A2 and MP5A3 are available with optional 4-position trigger groups; these are known as the MP5A4 and MP5A5 respectively. The trigger groups are marked with bullet pictograms rather than letters or numbers (each symbol represents the number of bullets that will be fired when the trigger is pulled and held rearward with a full magazine inserted in the weapon) and are fully ambidextrous (the selector lever is present on each side of the trigger housing). The additional setting of the fire selector, one place before the fully automatic setting, enables a two or three-shot burst firing mode. H&K offers dedicated training variants of these weapons, designated MP5A4PT and MP5A5PT (PT - Plastic Training), modified to fire a plastic 9x19mm PT training cartridge produced by Dynamit Nobel of Germany. These weapons operate like the standard MP5 but have a floating chamber and the bolt lacks both rollers to function properly when firing the lighter plastic projectiles. To help identify these weapons blue dots were painted on their cocking handles and additional lettering provided. The PT variant can be configured with various buttstocks and trigger groups and was developed for the West German Police and Border Guard.

A U.S. Marine fires an MP5.

The modular design of the MP5 offers multiple trigger groups: three-position "SEF" fire selector (positions: "S"-safe, "E"-semi automatic, "F" fully automatic. Located on left of receiver only); three-position fire selector (positions: safe, semiautomatic and a 2 or 3-round burst; selector lever is ambidextrous and its settings are marked with pictograms); four-position fire selector (positions: weapon safe, single fire, 2 or 3-round burst, full auto; ambidextrous selector; selector settings marked with pictograms); two-position fire control group (positions: weapon safe, single fire only; ambidextrous selector lever with pictograms) and a three-position fire selector group - the so called “Navy” trigger (settings: weapon safe, semi-automatic, fully automatic fire; ambidextrous selector lever; selector settings marked with bullet symbols again).

A USMC Military Police Special Reaction Team using the MP5-N.

A variant with the last trigger group designated the MP5-N (N – Navy) was developed in 1986 for the United States Navy. This model has a collapsible stock, a tritium-illuminated front sight post and a 225 mm (8.9 in) threaded barrel for use with a stainless steel sound suppressor made by Knight's Armament Company together with suppressed subsonic ammunition.

[edit] Civilian variants

The MP5SFA2 (SF - single-fire) is the same as the MP5A2 but is fitted with an ambidextrous semi-automatic only trigger group. Versions delivered after December 1991 are assembled with select-fire bolt carriers allowing fully automatic operation when used with the appropriate trigger module. Developed in 1986 in response to the American FBI solicitation for "9 mm Single-fire Carbines". The MP5SFA3 features a retractable metal stock.
The two-position trigger unit was used in the single-fire HK94 carbine that was produced specifically for the civilian market with a 420 mm (16.5 in) barrel.

[edit] Suppressed variants

In 1974 H&K initiated design work on a sound-suppressed variant of the MP5, designated the MP5SD (SD – Schalldämpfer German for "sound dampener"), which features an integral but detachable aluminium sound suppressor and a lightweight bolt. The weapon's 146 mm (5.7 in) barrel has 30 2.5 mm (0.1 in) ports drilled forward of the chamber through which escaping gases are diverted to the surrounding sealed tubular casing that is screwed on to threading on the barrel’s external surface just prior to the ported segment. The suppressor itself is divided into two stages; the initial segment surrounding the ported barrel serves as an expansion chamber for the propellant gases, reducing gas pressure to slow down the acceleration of the projectile. The second, decompression stage occupies the remaining length of the suppressor tube and contains a stamped metal helix separator with several compartments which increase the gas volume and decrease its temperature, deflecting the gases as they exit the muzzle, so muffling the exit report. The bullet leaves the muzzle at subsonic velocity, so it does not generate a sonic shock wave in flight. As a result of reducing the barrel’s length and venting propellant gases into the suppressor, the bullet’s muzzle velocity was lowered anywhere from 16% to 26% (depending on the ammunition used) while maintaining the weapon’s automation and reliability. The weapon was designed to be used with standard supersonic ammunition with the suppressor on at all times.
The MP5SD is produced exclusively by H&K in several versions: the MP5SD1 and MP5SD4 (both have a receiver end cap instead of a buttstock), MP5SD2 and MP5SD5 (equipped with a fixed synthetic buttstock) and the MP5SD3 and MP5SD6 (fitted with a collapsible metal stock). The MP5SD1, MP5SD2 and MP5SD3 use a standard "SEF" trigger group (from the MP5A2 and MP5A3), while the MP5SD4, MP5SD5 and MP5SD6 – a trigger module with a mechanically limited 3-round burst mode and ambidextrous selector controls (from the MP5A4 and MP5A5). A suppressed version was produced for the U.S. Navy - designated the MP5SD-N, which is a version of the MP5SD3 with a retractable metal stock, front sight post with tritium-illuminated dot and a stainless steel suppressor. This model has a modified cocking handle support to account for the slightly larger outside diameter of the suppressor. The design of the suppressor allows the weapon to be fired with water inside, should water enter the device during operation in or near water.

[edit] MP5K

U.S. Navy SEALs armed with MP5s on a training exercise.

In 1976 a shortened version of the MP5A2 was introduced; the MP5K (K from the German word Kurz = "short") was designed for close quarters battle use by clandestine operations and special services. The MP5K does not have a shoulder stock (the receiver end was covered with a flat end cap, featuring a buffer on the inside and a sling loop on the outside), and the bolt and receiver were shortened at the rear. The resultant lighter bolt led to a higher rate of fire than the standard MP5. The barrel, cocking handle and its cover were shortened and a vertical foregrip was used to replace the standard handguard. The barrel ends at the base of the foresight, which prevents the use of any sort of muzzle device.
The MP5K is produced (by Heckler & Koch and under license in Iran and Turkey) in four different versions: the MP5K, MP5KA4, MP5KA1, MP5KA5, where the first two variants have adjustable, open-type iron sights (with a notched rotary drum), and the two remaining variants - fixed open sights, however the front sight post was changed and a notch was cut into the receiver top cover. The MP5K retained the capability to use optical sights through the use of an adapter.
A civilian semiautomatic derivative of the MP5K known as the SP89 was produced that had a foregrip with a muzzle guard in place of the vertical grip.
In 1991 a further variant of the MP5K was developed, designated the MP5K-PDW (PDW – Personal Defense Weapon) that retained the compact dimensions of the MP5K but restored the fire handling characteristics of the full-size MP5A2. The MP5K-PDW uses a side-folding synthetic shoulder stock (made by the U.S. company Choate Machine and Tool), a “Navy” trigger group, a front sight post with a built-in tritium insert and a slightly lengthened threaded, three-lug barrel (analogous to the MP5-N). The stock can be removed and replaced with a receiver endplate; a rotary drum with apertures from the MP5A2 can also be used.

[edit] Larger caliber versions

In 1991, Heckler & Koch introduced the MP5/10 (chambered in 10mm Auto) and MP5/40 (chambered for the .40 S&W cartridge), which are based on the MP5A4 and MP5A5. These weapons were assembled in fixed and retractable stock configurations (without a separate designation) and are fed from translucent 30-round polymer box magazines.^[5] These weapons include a bolt hold-open device, which captures the bolt group in its rear position after expending the last cartridge from the magazine. The bolt is then released by pressing a lever positioned on the left side of the receiver. Both weapons use a barrel with 6 right-hand grooves and a 380 mm (1:15 in) twist rate, and like the MP5-N, both have a 3-lugged muzzle device and a tritium-illuminated front sight aiming dot.

[edit] Variants list

Cross section diagram of an MP5SD early model suppressor, from 1971 patent. Vented barrel surrounded by metal mesh packing in the expansion chambers, followed by conical baffles in the forward chambers.

MP5K-PDW (early prototype, lacking 'Navy' trigger group and lugged barrel).

The MP5SD3.

 

M16 rifle

Rifle, 5.56 mm, M16
From top to bottom: M16A1, M16A2, M4A1, M16A4
Type	Assault rifle
Place of origin	United States
Service history
In service	1963–Present
Used by	See Users
Wars	Vietnam War–Present
Production history
Designer	Eugene Stoner L. James Sullivan [1]
Designed	1957
Manufacturer	Colt Defense FN Herstal H & R Firearms General Motors Hydramatic Division
Produced	1960–Present
Number built	~8 million [2]
Variants	See Variants
Specifications (M16A2)
Weight	7.8 lb (3.5 kg) (unloaded) 8.79 lb (4.0 kg) (loaded)
Length	39.625 in (1,010 mm)
Barrel length	20 in (508 mm)
Cartridge	5.56x45mm NATO
Action	Gas-operated, rotating bolt
Rate of fire	12-15 rounds/min sustained, 45-60 rounds/min semi-automatic, & 700–950 rounds/min cyclic
Muzzle velocity	3,110 ft/s (948 m/s) [3]
Effective range	550 Meters (point target), 800 Meters (area target)
Feed system	Various STANAG magazines

 

M16 rifle

The M16 (more formally Rifle, Caliber 5.56 mm, M16) is the United States military designation for the AR-15 rifle. Colt purchased the rights to the AR-15 from ArmaLite and currently uses that designation only for semi-automatic versions of the rifle. The M16 rifle fires the 5.56x45mm cartridge and can produce massive wounding and hydrostatic shock effects when the bullet impacts at high velocity and yaws in tissue leading to fragmentation and rapid transfer of energy.^[4][5][6]
The M16 entered United States Army service as the M16 and was put into action for jungle warfare in South Vietnam in 1963,^[7] becoming the standard U.S. rifle of the Vietnam War by 1969,^[8] replacing the M14 rifle in that role. The U.S. Army retained the M14 in CONUS, Europe, and South Korea until 1970. Since the Vietnam War, the M16 rifle family has been the primary infantry rifle of the U.S. military. With its variants, it has been in use by 15 NATO countries, and is the most produced firearm in its caliber.

Introduction

The M16 is a lightweight, 5.56 mm, air-cooled, gas-operated, magazine-fed assault rifle, with a rotating bolt, actuated by direct impingement gas operation. The rifle is made of steel, 7075 aluminum alloy, composite plastics and polymer materials.
The U.S. Air Force's rifle, the M16, and the United States Marine Corps and Army rifle, the XM16E1, were the first versions of the M16 rifle fielded. Soon, the U.S. Army standardized the XM16E1 as the M16A1 rifle, an M16 with a forward assist feature requested by the Army. All of the early versions were chambered to fire the M193/M196 cartridge in the semi-automatic and the automatic firing modes. This occurred in the early 1960s, with the Army issuing it in late 1964.^[9] Commercial AR-15s were first issued to Special Forces troops in spring of 1964.^[10]

A U.S. soldier on NBC exercise, holding an M16A1 rifle and wearing an M40 Field Protective Mask. Note the receiver, forward assist and the barrel flash suppressor.

The M16A2 rifle entered service in the 1980s, chambered to fire the standard NATO cartridge, the Belgian-designed M855/M856 cartridge.^[9] The M16A2 is a select-fire rifle (semi-automatic fire, three-round-burst fire) incorporating design elements requested by the Marine Corps:^[9] an adjustable, windage rear-sight; a stock 5/8-inch longer; heavier barrel; case deflector for left-hand shooters; and cylindrical handguards.^[9] The fire mode selector is on the receiver's left side. The M16A2 is still the primary rifle in the U.S. Navy, Coast Guard, Air Force, and still is in heavy use in the Army and Marine Corps.^{[citation needed]}
The M16A3 rifle is an M16A2 rifle with an M16A1's fire control group (semi-automatic fire, automatic fire) used only by the U.S. Navy.
The M16A4 rifle was standard issue for the United States Marine Corps in Operation Iraqi Freedom; it replaced the M16A2 in front line units. In the U.S. Army the M16A2 rifle is being supplemented with two rifle models, the M16A4 and the M4 carbine as the standard issue assault rifle. The M16A4 has a flat-top receiver developed for the M4 carbine, a handguard with four Picatinny rails for mounting a sight, laser, night vision device, forward handgrip, removable handle, or a flashlight.
The M16 rifle is principally manufactured by Colt and Fabrique Nationale de Herstal (under a U.S. military contract since 1988 by FNH-USA; currently in production since 1991, primarily M16A2, A3, and A4), with variants made elsewhere in the world. Versions for the U.S. military have also been made by H & R Firearms^[11] General Motors Hydramatic Division^[12] and most recently by Sabre Defence.^[13] Semi-automatic versions of the AR-15 are popular recreational shooting rifles, with versions manufactured by other small and large manufacturers in the U.S.^[14]

[edit] History

[edit] Summary

The M16A1 seen here fitted with an AN/PVS-2 night vision scope.

ArmaLite sold its rights to the AR-15 to Colt in 1959.^[15] The AR-15 was first adopted in 1962 by the United States Air Force, ultimately receiving the designation M16. The U.S. Army began to field the XM16E1 en masse in 1968 with most of them going to the Republic of Vietnam, and the newly organized and experimental Airmobile Divisions, the 1st Air Cavalry Division in particular. The U.S. Marine Corps in South Vietnam also experimented with the M16 rifle in combat during this period. The XM16E1 was standardized as the M16A1 in 1967. This version remained the primary infantry rifle of U.S. forces in South Vietnam until the end of the war in 1975, and remained with all U.S. military ground forces after it had replaced the M14 service rifle in 1970 in CONUS, Europe (Germany), and South Korea; when it was supplemented by the M16A2. During the early 1980s a roughly standardized load for this ammunition was adopted throughout NATO (see: 5.56x45mm NATO).
The M16A3 is a fully-automatic variant of the M16A2, issued within the United States Navy. The M16A2 is currently being supplemented by the M16A4, which incorporates the flattop receiver unit developed for the M4 carbine, and Picatinny rail system. M16A2s are still in stock with the U.S. Army and Marine Corps, but are used primarily by reserve and National Guard units as well as by the U.S. Air Force.^{[citation needed]}
The M16 rifle design, including variant or modified version of it such as the Armalite/Colt AR-15 series, AAI M15 rifle; AP74; EAC J-15; SGW XM15A; any 22-caliber rimfire variant, including the Mitchell M16A-1/22, Mitchell M16/22, Mitchell CAR-15/22, and AP74 Auto Rifle, is a prohibited and restricted weapon in Canada.^[16]

[edit] Project SALVO

An M16 (third from top), an AR-10 and a semi-automatic AR-15 "Sporter" along with other Vietnam War era rifles.

In 1948, the Army organized the civilian Operations Research Office, mirroring similar operations research organizations in the United Kingdom. One of their first efforts, Project ALCLAD, studied body armor and the conclusion was that they would need to know more about battlefield injuries in order to make reasonable suggestions.^[17] Over 3 million battlefield reports from World War I and World War II were analyzed and over the next few years they released a series of reports on their findings.^[17]
The conclusion was that most combat takes place at short range. In a highly mobile war, combat teams ran into each other largely by surprise; and the team with the higher firepower tended to win. They also found that the chance of being hit in combat was essentially random; accurate "aiming" made little difference because the targets no longer sat still. The number one predictor of casualties was the total number of bullets fired.^[17] Other studies of behavior in battle revealed that many U.S. infantrymen (as many as 2/3) never actually fired their rifles in combat. By contrast, soldiers armed with rapid fire weapons were much more likely to have fired their weapons in battle.^[18] These conclusions suggested that infantry should be equipped with a fully-automatic rifle of some sort in order to increase the actual firepower of regular soldiers. It was also clear, however, that such weapons dramatically increased ammunition use and in order for a rifleman to be able to carry enough ammunition for a firefight they would have to carry something much lighter.
Existing rifles met none of these criteria. Although it appeared the new 7.62 mm T44 (precursor to the M14) would increase the rate of fire, its heavy 7.62 mm NATO cartridge made carrying significant quantities of ammunition difficult. Moreover, the length and weight of the weapon made it unsuitable for short range combat situations often found in jungle and urban combat or mechanized warfare, where a smaller and lighter weapon could be brought to bear faster.

M16A1

These efforts were noticed by Colonel René Studler, U.S. Army Ordnance's Chief of Small Arms Research and Development. Col. Studler asked the Aberdeen Proving Ground to submit a report on the smaller caliber weapons. A team led by Donald Hall, director of program development at Aberdeen, reported that a .22 inch (5.56 mm) round fired at a higher velocity would have performance equal to larger rounds in most combat.^[19] With the higher rate of fire possible due to lower recoil it was likely such a weapon would inflict more casualties on the enemy. His team members, notably William C. Davis, Jr. and Gerald A. Gustafson, started development of a series of experimental .22 (5.56 mm) cartridges. In 1955, their request for further funding was denied.
A new study, Project SALVO, was set up to try to find a weapon design suited to real-world combat. Running between 1953 and 1957 in two phases, SALVO eventually suggested that a weapon firing four rounds into a 20-inch (508 mm) area would double the hit probability of existing semi-automatic weapons.
In the second phase, SALVO II, several experimental weapons concepts were tested. Irwin Barr of AAI Corporation introduced a series of flechette weapons, starting with a shotgun shell containing 32 darts and ending with single-round flechette "rifles". Winchester and Springfield Armory offered multi-barrel weapons, while ORO's own design used two .22, .25 or .27 caliber bullets loaded into a single .308 Winchester or .30-06 cartridge.

[edit] Eugene Stoner

A U.S. soldier with M16A2 at Schofield Barracks, Hawaii. The United States Army did not place a large order for the A2 model until 1986.

Meanwhile testing of the 7.62 mm T44 continued, and Fabrique Nationale also submitted their new FN FAL via the American firm Harrington & Richardson as the T48. The T44 was selected as the new battle rifle for the U.S. Army (rechristened the M14) despite a strong showing by the T48.^{[citation needed]}
In 1954, Eugene Stoner of the newly-formed ArmaLite helped develop the 7.62 mm AR-10. Springfield's T44 and similar entries were conventional rifles using wood for the "furniture" and otherwise built entirely of steel using mostly forged and machined parts. ArmaLite was founded specifically to bring the latest in designs and alloys to firearms design, and Stoner felt he could easily beat the other offerings.
The AR-10's receiver was made of forged and milled aluminium alloy instead of steel. The barrel was mated to the receiver by a separate hardened steel extension to which the bolt locked. This allowed a lightweight aluminum receiver to be used while still maintaining a steel-on-steel lockup. The bolt was operated by high-pressure combustion gases taken from a hole in the middle of the barrel directly through a tube above the barrel to a cylinder created in the bolt carrier with the bolt carrier itself acting as a piston. Traditional rifles located this cylinder and piston close to the gas vent. The stock and grips were made of a glass-reinforced plastic shell over a rigid foam plastic core. The muzzle brake was fabricated from titanium. Over Stoner's objections, various experimental composite and 'Sullaloy' aluminum barrels were fitted to some AR-10 prototypes by ArmaLite's president, George Sullivan. The Sullaloy barrel was made entirely of heat-treated aluminum, while the composite barrels used aluminum extruded over a thin stainless steel liner.
Meanwhile the layout of the weapon itself was also somewhat different. Previous designs generally placed the sights directly on the barrel, using a bend in the stock to align the sights at eye level while transferring the recoil down to the shoulder. This meant that the weapon tended to rise when fired making it very difficult to control during fully-automatic fire. The ArmaLite team used a solution previously used on weapons such as the German FG 42 and Johnson light machine gun; they located the barrel in line with the stock, well below eye level, and raised the sights to eye level. The rear sight was built into a carrying handle over the receiver.
Despite being over 2 lb (0.9 kg) lighter than the competition, the AR-10 offered significantly greater accuracy and recoil control. Two prototype rifles were delivered to the U.S. Army's Springfield Armory for testing late in 1956. At this time, the U.S. armed forces were already two years into a service rifle evaluation program, and the AR-10 was a newcomer with respect to older, more fully-developed designs. Over Stoner's continued objections, George Sullivan had insisted that both prototypes be fitted with composite aluminum/steel barrels. Shortly after a composite barrel burst on one prototype in 1957, the AR-10 was rejected. The AR-10 was later produced by a Dutch firm, Artillerie Inrichtingen, and saw limited but successful military service with several foreign nations such as Sudan, Guatemala, and Portugal. Portugal deployed a number of AR-10s for use by its airborne (Caçadores Pára-quedista) battalions, and the rifle saw considerable combat service in Portugal's counter-insurgency campaigns in Angola and Mozambique.^[20] Some AR-10 rifles were still in service with airborne forces serving during the withdrawal from Portuguese Timor in 1975.

[edit] CONARC

In 1957, a copy of Gustafson's funding request from 1955 found its way into the hands of General Willard G. Wyman, commander of the U.S. Continental Army Command. He immediately put together a team to develop a .223 caliber (5.56 mm) weapon for testing. Their finalized request called for a select-fire weapon of 6 pounds (2.7 kg) when loaded with 20 rounds of ammunition. The bullet had to penetrate a standard U.S. steel helmet, body armor, or a 0.135 inch (3.4 mm) steel plate and retain a velocity in excess of the speed of sound at 500 yards (460 m), while equaling or exceeding the "wounding" ability of the .30 Carbine.^[17][21]
Wyman had seen the AR-10 in an earlier demonstration, and impressed by its performance he personally suggested that ArmaLite enter a weapon for testing using a 5.56 mm cartridge designed by Winchester.^[17] Their first design, using conventional layout and wooden furniture, proved to be too light. When combined with a conventional stock, recoil was excessive in fully automatic fire. Their second design was simply a scaled-down AR-10, and immediately proved much more controllable. Winchester entered a design based loosely on their M1 carbine, and Earle Harvey of Springfield attempted to enter a design, but was overruled by his superiors at Springfield, who refused to divert resources from the T44.

A U.S. Marine takes aim with an M16A2 fitted with the M203 40 mm grenade launcher.

In the end, ArmaLite's AR-15 had no competition. The lighter round allowed the rifle to be scaled down, and was smaller and lighter than the previous AR-10. The AR-15 weighed only around 5.5 lb (2.5 kg) empty, 6 lb (2.7 kg) loaded (with a 20 round magazine).
During testing in March 1958, rainwater caused the barrels of both the ArmaLite and Winchester rifles to burst, causing the Army to once again press for a larger round, this time at .258 in (6.6 mm). Nevertheless, they suggested continued testing for cold-weather suitability in Alaska. Stoner was later asked to fly in to replace several parts, and when he arrived he found the rifles had been improperly reassembled. When he returned he was surprised to learn that they too had rejected the design even before he had arrived; their report also endorsed the .258 in (6.6 mm) round. After reading these reports, General Maxwell Taylor became dead-set against the design, and pressed for continued production of the M14.
Not all the reports were negative. In a series of mock-combat situations testing the AR-15, M14 and AK-47, the Army found that the AR-15's small size and light weight allowed it to be brought to bear much more quickly, just as CONARC had suggested. Their final conclusion was that an 8-man team equipped with the AR-15 would have the same firepower as a current 11-man team armed with the M14.
At this point, Fairchild had spent $1.45 million in development expenses, and wished to divest itself of its small-arms business. Fairchild sold production rights for the AR-15 to Colt Firearms in December 1959, for only $75,000 cash and a 4.5% royalty on subsequent sales. In 1960, ArmaLite was reorganized, and Stoner left the company.

[edit] M16 adoption

Curtis LeMay viewed a demonstration of the AR-15 in July 1960. In the summer of 1961, General LeMay had been promoted to the position of USAF Chief of Staff, and requested an order of 80,000 AR-15s for the U.S. Air Force.^[22] However under the recommendation of General Maxwell D. Taylor, who advised the Commander in Chief that having two different calibers within the military system at the same time would be problematic, President Kennedy turned down the request.^[22] However, Advanced Research Projects Agency, which had been created in 1958 in response to the Soviet Sputnik program, embarked on project AGILE in the spring of 1961. AGILE's priority mission was to devise inventive fixes to the communist problem in South Vietnam.^[23] In October 1961, William Godel, a senior man at ARPA, sent 10 AR-15s to South Vietnam to let the allies test them. The reception was enthusiastic, and in 1962 another 1,000 AR-15s were sent to South Vietnam.^[24] Special Operations units and advisers working with the South Vietnamese troops filed battlefield reports lavishly praising the AR-15 and the stopping effectiveness of the 5.56 mm cartridge, and pressed for its adoption. However, what no one knew, except the men directly using the AR-15s in Vietnam, were the devastating kills^[25] made by the new rifle, photographs of which, showing enemy casualties made by the .223 (5.56 mm) bullet remained classified into the 1980s.^[25]
The damage caused by the .223 (5.56mm) "varmint"^[25] bullet was easily accounted for. Standard U.S. rifles generally had 12 inch rifling twists inside their barrels (one complete bullet rotation within 12 inches), whereas the AR-15, as designed by Stoner, was to have a 1 in 14 inch rifling twist, as rapid spraying of projectiles at close range would be the norm rather than long range accuracy. However Colt, with its antiquated equipment, had made some of the AR-15s with up to 18 inches per total bullet rotation,^[26] thus creating a bullet's flight to wobble while en route to target. The impact of these projectiles on human flesh created horrible wounds; as well as very few prisoners of war.^[27]
U.S. Secretary of Defense Robert McNamara now had two conflicting views: the ARPA report favoring the AR-15 and the Pentagon's position on the M14. Even President John F. Kennedy expressed concern, so McNamara ordered Secretary of the Army Cyrus Vance to test the M14, the AR-15 and the AK-47. The Army's test report stated only the M14 was suitable for Army use, but Vance wondered about the impartiality of those conducting the tests. He ordered the Army Inspector General to investigate the testing methods used, who reported that the testers showed favor to the M14.

U.S. Soldier cleans his XM16E1 during the Vietnam War in 1966.

Secretary Robert McNamara ordered a halt to M14 production in January 1963, after receiving reports that M14 production was insufficient to meet the needs of the armed forces. Secretary McNamara had long been a proponent of weapons program consolidation among the armed services. At the time, the AR-15 was the only rifle that could fulfill a requirement of a "universal" infantry weapon for issue to all services. McNamara ordered the weapon be adopted unmodified, in its current configuration, for immediate issue to all services, despite receiving reports noting several deficiencies with the M16 as a service rifle, including the lack of a chrome-lined bore and chamber, the 5.56 mm projectile's instability under arctic conditions,^{[citation needed]} and the fact that large quantities of 5.56 mm ammunition required for immediate service were not available.^{[citation needed]} In addition, the Army insisted on the inclusion of a forward assist to help push the bolt into battery in the event that a cartridge failed to seat in the chamber through fouling or corrosion. Colt had argued the rifle was a self-cleaning design, requiring little or no maintenance. Colt, Eugene Stoner, and the U.S. Air Force believed that a forward assist needlessly complicated the rifle, adding about $4.50 to its procurement cost with no real benefit. As a result, the design was split into two variants: the Air Force's M16 without the forward assist, and for the other service branches, the XM16E1 with the forward assist.
In November 1963, McNamara approved the Army's order of 85,000 XM16E1s for jungle warfare operations;^[28] and to appease General LeMay, the Air Force was granted an order for another 19,000 M16s.^[17][29] Meanwhile, the Army carried out another project, the Small Arms Weapons Systems, on general infantry firearm needs in the immediate future. They recommended the immediate adoption of the weapon. Later that year the Air Force officially accepted their first batch as the United States Rifle, Caliber 5.56 mm, M16.
The Army immediately began to issue the XM16E1 (re-named M16A1 on its adoption) to infantry units but the rifle was initially delivered without adequate cleaning supplies or instructions. When the M16 reached Vietnam with U.S. troops in March 1965, reports of jamming and malfunctions in combat began to surface. Although the M14 featured a chrome-lined barrel and chamber to resist corrosion in combat conditions, neither the bore nor the chamber of the M16/XM16E1 was chrome-lined. Several documented accounts of troops killed by enemy fire with jammed rifles broken-down for cleaning eventually brought a Congressional investigation.^[30]

“

We left with 72 men in our platoon and came back with 19, Believe it or not, you know what killed most of us? Our own rifle. Practically every one of our dead was found with his [M16] torn down next to him where he had been trying to fix it. - Marine Corps Rifleman, Vietnam.[30]

”

The root cause of the jamming issues turned out to be a problem with the powder for the ammunition. In 1964 when the Army was informed that DuPont could not mass-produce the nitrocellulose-based powder to the specifications demanded by the M16, the Olin Mathieson Company provided a high-performance ball propellant of nitrocellulose and nitroglycerin. While the Olin WC 846 powder was capable of firing an M16 5.56 mm round at the desired 3,300 ft. per second, it had the unintended consequence of increasing the automatic rate of fire from 850 to 1000 rounds per minute. This would leave behind dirty residue and making the M16 more likely to jam. The problem was resolved by fitting the M16 with a buffer system, slowing the rate of fire back down to 650 to 850 rounds per minute and outfitting all newly produced M16's with a chrome-plated chamber.^[31]
On February 28, 1967, the XM16E1 was standardized as the M16A1. Major revisions to the design followed. The rifle was given a chrome-lined chamber (and later, the entire bore) to eliminate corrosion and stuck cartridges, and the rifle's recoil mechanism was re-designed to accommodate Army-issued 5.56 mm ammunition. Rifle cleaning tools and powder solvents/lubricants were issued. Intensive training programs in weapons cleaning were instituted, and a comic book style manual was circulated among the troops to demonstrate proper maintenance.^[17] The reliability problems of the M16 diminished quickly, although the rifle's reputation continued to suffer.^[17]
According to a February 1968 Department of Defense report the M16 rifle achieved widespread acceptance by U.S. troops in Vietnam. Only 38 of 2100 individuals queried wanted to replace the M16 with another weapon. Of those 38, 35 wanted the CAR-15 (a shorter version of the M16) instead.^[32]

[edit] NATO standards

German Army soldiers of the 13th Panzergrenadier Division qualify with the M16A2 at Würzburg, as part of a partnership range with the U.S. 1st Infantry Division.

In March 1970, the U.S. stated that all NATO forces would eventually adopt the 5.56x45mm cartridge. This shift represented a change in the philosophy of the military's long-held position about caliber size. It was particularly unsettling to the British, whose military had adopted the larger 7.62mm NATO cartridge over their own .280 caliber (7.1 mm) nearly 20 years earlier. From the British point of view, the realization by the U.S. of the effectiveness of a smaller caliber was a belated one.
By the middle of the 1970s, other armies were also looking at an M16-style weapon. A NATO standardization effort soon started, and tests of various rounds were carried out starting in 1977. The U.S. offered their original design, the M193, with no modifications, but there were concerns about its penetration in the face of the wider introduction of body armor. The British offered a modified 5.56 mm round, using a longer and thinner bullet of 4.85 mm. The round had somewhat better ballistics and considerably better penetration, able to reach 600 m and meet their requirements for a squad automatic weapon (light machine gun). The Germans proposed a new 4.7 mm caseless round, which was considerably lighter while offering similar ballistics to the original U.S. design. However, there was distrust in the caseless system due to the possibility of cook off. A final design was offered by the Belgians. Their SS109 round was based on the U.S. cartridge but included a new bullet design, with the same 5.56 mm caliber, but with a small steel tip added to improve penetration.
Testing soon showed that the British and Belgian designs were roughly equal, both outperforming the original U.S. design. In order to get full performance from tracer versions of the SS109, however, barrels would have to use different rifling. Existing 1:12 inch (or 1:300mm) twist barrels reduced the effective range of the SS109 to 90 meters due to lack of stability. While the ideal twist rate for the SS109 projectile is 1:9 inch/1:229mm, a 1:7 inch/1:180mm twist rate was chosen to stabilize the much longer L110 tracer. This tracer was designed to complement the SS109's ballistic performance. The M196 tracer (complement to the M193 ball round) had a burn-out range of 450 meters where the L110 tracer was bright to 800 meters. In the end the Belgian round was chosen. The U.S. Marine Corps was first to adopt the round with the M16A2, introduced in 1982. This was to become the standard U.S. military rifle. The NATO 5.56x45mm standard ammunition produced for U.S. forces is designated M855 for the ball round using an SS109 type projectile and M856 for the tracer using the L110 type projectile.
The M16 series has four main versions: M16A1, M16A2, M16A3, and M16A4. Total worldwide production of M16-style weapons since the design's inception has been approximately 8 million.^[2]

[edit] Design

Top drawing is of an A2-style rifle; bottom drawing is of an A2-style rifle with A1 rear sights (as with the C7)

The M16's receivers are made of 7075 aluminum alloy, its barrel, bolt, and bolt carrier of steel, and its handguards, pistol grip, and buttstock of plastics. Early models were especially lightweight at 6.5 lb (2.9 kg) without magazine and sling. This was significantly less than older 7.62 mm "battle rifles" of the 1950s and 1960s. It also compares with the 6.5 lb (2.9 kg) AKM without magazine.^[33] M16A2 and later variants (A3 & A4) weigh more (8.5 lb (3.9 kg) loaded) because of the adoption of a thicker barrel profile. The thicker barrel is more resistant to damage when handled roughly and is also slower to overheat during sustained fire. Unlike a traditional "bull" barrel that is thick its entire length, the M16A2's barrel is only thick forward of the handguards. The barrel profile under the handguards remained the same as the M16A1 for compatibility with the M203 grenade launcher. The rifle is the same length as the M16A2.
One distinctive ergonomic feature is a plastic or metal stock directly behind the action, which contains a recoil spring.^[34] This serves the dual function of operating spring and recoil buffer.^[34] The stock being in line with the bore reduces muzzle rise, especially during automatic fire. Because recoil does not significantly shift the point of aim, faster follow-up shots are possible and user fatigue is reduced.
Another distinctive ergonomic feature is a carrying handle on top of the receiver, with an integrated rear sight assembly and charging handle. This design is a by-product of the original design where the carry handle served to protect the charging handle and mount a scope.^[34] In practice, the handle is rarely used to carry the weapon and doing so is expressly prohibited in many military organizations, as it is considered unsafe.^{[citation needed]} Holding the weapon by the pistol grip provides quicker response time and better "muzzle awareness," while a shoulder sling provides a more convenient option when response time is not a concern.^{[citation needed]} More importantly, with the sight plane 2.5 in (63.5 mm) over the bore, the M16 has an inherent parallax problem that can be confounding to shooters. At closer ranges (typically inside 15–20 meters), the shooter must aim high in order to place shots where desired.
Newer models have a "flattop" upper receiver with a Picatinny rail, to which the user can attach either a conventional sighting system or numerous optical devices such as night vision scopes.
The M16 utilizes direct impingement gas operation; energy from high-pressure gas tapped from a non-adjustable port built into the front sight assembly actuates the moving parts in the weapon. Combustion gases travel via a gas tube above the barrel directly into a chamber in the bolt carrier behind the bolt itself, pushing the carrier away from the bolt. This reduces the number of moving parts by eliminating the need for a separate piston and cylinder and it provides better performance in rapid fire by keeping reciprocating masses on the same axis as the bore.^{[citation needed]}
The primary criticism of direct impingement is that fouling and debris from expended gunpowder is blown directly into the breech. As the superheated combustion gas travels down the tube, it expands and cools. This cooling causes vaporized matter to condense as it cools depositing a much greater volume of solids into the operating components of the action. The increased fouling can cause malfunctions if the rifle is not cleaned as frequently as should be. The amount of sooting deposits tends to vary with powder specification, caliber, and gas port design.

Camouflaged M16 rifle

In April 2010 TACOM Life Cycle Management Command issued permission for soldiers to camouflage M4/M16 weapons with paint if given command approval.^[35]