Heckler & Koch MP5


The MP5 is a 9x19mm Parabellum submachine gun, developed in the 1960s by a team of engineers from the German small arms manufacturer Heckler & Koch GmbH of Oberndorf am Neckar. There are over 100 variants of the MP5, including some semi-automatic versions.
The MP5 is one of the most widely used submachine guns in the world, having been adopted by 40 nations and numerous military, law enforcement, intelligence, and security organizations. It was widely used by SWAT teams in North America, but has since been supplanted by M16 variants in the 21st century.
In 1999, Heckler & Koch developed the Heckler & Koch UMP, the MP5's successor; both are available, but the UMP has not met the same level of success.

History

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. The first type was chambered for 7.62×51mm NATO, the second for the 7.62×39mm M43 round, the third for the intermediate 5.56×45mm NATO caliber, and the fourth type for the 9×19mm 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 two years later it was adopted by the German Federal Police, border guard and army special forces, referring to as the "MP64" or later "MP5". The MP5A1 was introduced in the late '60s, which the first model to have the iconic ring front sight and the slimline handguard. In 1970, the MP5A2 and MP5A3 was introduced. It also had its first film "The Millions Games" released on October 18, 1970. In 1974, the MP5SD was introduced, which is a suppressed variant of the MP5. It was used in the Vietnam War in 1975 by the Green Berets. In 1976, the MP5K was introduced as a request for a variant for South America. In 1977, the standard 20 & 30 round, curved steel magazines were introduced for the MP5A2 and MP5A3 design. In 1978, the Tropical forearm was introduced to be produced with the MP5.
In 1980, the MP5 achieved iconic status as a result of British special forces regiment the SAS when they stormed the Iranian Embassy in London, live on television, rescuing hostages and killing five terrorists during Operation Nimrod.
The MP5 has become a mainstay of SWAT units of law enforcement agencies in the United States since then. However, in the late 1990s, as a result of the North Hollywood shootout, police special response teams have supplanted most MP5s with AR-15-based rifles.
The MP5 is manufactured under license in several nations including Greece, Iran, Mexico, Pakistan, Saudi Arabia, Sudan, Turkey, and the United Kingdom.

Design details

The primary version of the MP5 family is the MP5A2, which is a lightweight, air-cooled, selective fire delayed blowback operated 9×19mm Parabellum weapon with a roller-delayed bolt. It fires from a closed bolt position.
The fixed, free floating, cold hammer-forged barrel has 6 right-hand grooves with a 1 in 250 mm rifling twist rate and is pressed and pinned into the receiver.

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 or a 30-round capacity.
The adjustable iron sights consist of a rotating rear diopter drum and a front post installed in a hooded ring. The rear sight is mechanically adjustable for both windage and elevation with the use of a special tool, being adjusted at the factory for firing at with standard FMJ 9×19mm NATO ammunition. The rear sight drum provides four apertures of varying diameters used to adjust the diopter system, according to the user's preference and tactical situation. Changing between apertures does not change the point of impact down range. For accurate shooting the user should select the smallest aperture that still allows an equal circle of light between the rear sight aperture and the outside of the front sight hood ring.
The MP5 has a hammer firing mechanism. The trigger group is housed inside an interchangeable polymer trigger module and equipped with a three-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 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 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 approximately 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.

Operating mechanism

The bolt rigidly engages the barrel extension—a cylindrical component welded to the receiver into which the barrel is pinned. 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.
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 this force 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.
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 9×19mm Parabellum cartridge is relatively low powered, the bolt does not have an anti-bounce device like the G3, but instead the bolt carrier contains of 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. 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.

Accessories

In the early 1970s, HK introduced a conversion kit for the MP5 that enables it to use rimfire ammunition. 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. It was sold mostly to law enforcement agencies as a way to train recruits on handling the MP5. It used ammunition that was cheaper and had a lower recoil than 9×19mm Parabellum. This reduced training costs and built up skill and confidence in the operators before transitioning them to the full-bore model.

Barrel accessories

Threading is provided at the muzzle to work with certain muzzle devices made by Heckler & Koch, including: a slotted flash suppressor, blank firing attachment, an adapter for launching rifle grenades and a cup-type attachment used to launch tear gas grenades. An optional three-lugged barrel is also available for mounting a quick-detachable suppressor.

Receiver

The receiver housing has a proprietary claw-rail mounting system that permits the attachment of a standard Heckler & Koch quick-detachable scope mount. It can be used to mount daytime optical sights, night sights, 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.
A Picatinny rail adapter can be placed on top that locks into the claw rails. This allows the mounting of STANAG scopes and has a lower profile than the claw-rail system.

Handguard

Aftermarket replacement handguards with Picatinny rails are available. Single-rail models have a Picatinny rail along the bottom and triple-rail models have rails along the bottom and sides. They allow the mounting of accessories like flashlights, laser pointers, target designators, vertical foregrips, and bipods.

Variants

The MP5A2 has a fixed buttstock, whereas the compact MP5A3 has a retractable metal stock. The stockless MP5A1 has a buttcap with a sling mount for concealed carry; the MP5K series was a further development of this idea.
The MP5A4 and MP5A5 models, which were introduced in 1974, are available with four-position trigger groups. The pistol grips are straight, lacking the contoured grip and thumb groove of the MP5A1, MP5A2, and MP5A3. The selector lever stops are marked with bullet pictograms rather than letters or numbers and are fully ambidextrous. The additional setting of the fire selector, one place before the fully automatic setting, enables a two or three-shot burst firing mode.
A variant with the last trigger group designated the MP5-N was developed in 1986 for the United States Navy. This model has a collapsible stock, a tritium-illuminated front sight post and a threaded barrel for use with a stainless steel sound suppressor made by Knight's Armament Company together with quieter subsonic ammunition. It had ambidextrous controls, a straight pistol grip, pictogram markings, and originally had a four-position selector. This was replaced with a similar three-position ambidextrous selector after an improperly-reassembled trigger group spontaneously fired during an exercise. The "Navy"-style ambidextrous trigger group later became standard, replacing the classic "SEF".
TypePositionsSettingsLocation
SEF3-positionSafe, semi-auto, burst-fire Left-side
SF2-positionSafe & semi-auto Ambidextrous
Navy4-positionSafe, semi-auto, 2- or 3-round burst, fully autoAmbidextrous
Navy3-positionSafe, semi-auto, fully autoAmbidextrous

Training

H&K offers dedicated training variants of these weapons, designated MP5A4PT and MP5A5PT, modified to fire a plastic 9×19mm PT training cartridge produced by Dynamit Nobel of Germany. These weapons operate like the standard MP5 but have a floating chamber and both rollers have been omitted from the bolt 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.

Semi-auto

The MP5SFA2 was developed in 1986 in response to the American FBI solicitation for a "9 mm Single-fire Carbine". It is the same as the MP5A2 but is fitted with an ambidextrous semi-automatic only trigger group. The MP5SFA3 is similar except it has a retractable metal stock like the MP5A3. Versions delivered after December 1991 are assembled with select-fire bolt carriers allowing fully automatic operation when used with the appropriate trigger module.
The semi-automatic "MP5SF" models are widely used by British police forces including London's Metropolitan Police Service Specialist Firearms Command, Diplomatic Protection Group, Authorised firearms officers, and the Police Service of Northern Ireland to name a few.
The two-position trigger unit was used in the single-fire HK94 carbine that was produced specifically for the civilian market with a barrel.

Suppressed

In 1974, H&K initiated design work on a sound-suppressed variant of the MP5, designated the MP5SD, which features an integral but detachable aluminium sound suppressor and a lightweight bolt. The weapon's barrel has 30 ports drilled forward of the chamber through which escaping gases are diverted to the surrounding sealed tubular casing that is screwed onto 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% 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, MP5SD2 and MP5SD5 and the MP5SD3 and MP5SD6. The MP5SD1, MP5SD2 and MP5SD3 use a standard 'SEF' trigger group, while the MP5SD4, MP5SD5, and MP5SD6 use the 'Navy' trigger group—a trigger module with a mechanically limited 3-round burst mode and ambidextrous selector controls. 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.

MP5K

In 1976, a shortened machine pistol version of the MP5A2 was introduced; the MP5K was designed for close quarters battle use by clandestine operations and special services. The MP5K does not have a shoulder stock, 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 front sight, which prevents the use of any sort of muzzle device.
The MP5K is produced in four different versions: the MP5K, MP5KA4, MP5KA1, MP5KA5, where the first two variants have adjustable, open-type iron sights, 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 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, a "Navy" trigger group, a front sight post with a built-in tritium insert and a slightly lengthened threaded, three-lug barrel. The stock can be removed and replaced with a receiver endplate; a rotary drum with apertures from the MP5A2 can also be used.

Larger caliber

In 1992, Heckler & Koch introduced the MP5/10 and MP5/40, which are based on the MP5A4 and MP5A5. These weapons were assembled in fixed and retractable stock configurations and are fed from translucent 30-round polymer box magazines. 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 twist rate, and like the MP5-N, both have a 3-lugged muzzle device and a tritium-illuminated front sight aiming dot.
Problems with the MP5/10 and MP5/40 led to their discontinuation in 2000, although Heckler & Koch continues to provide support and spare parts.

List

A barrel-mounted vertical foregrip and a ventilated barrel shroud were available for the stock HK94. The HK94 was imported from 1983 to 1989, in three different configurations:
As an aftermarket modification, a PSG-1 trigger pack with target pistol grip and match trigger could be added by a gunsmith by changing the ejector and hammer spring. The 6× Leupold scope was calibrated for.223 Remington rounds, so other scopes were often substituted.
The AT-94 series, imported by ATI and designed for the American market, is modified so that full-auto and 90-series trigger packs cannot be fitted. Zenith started importing the Z-5 rifle, Z-5Rs, and Z-5K. With the exception of the Z-5 rifle, they were imported as pistols, but a stock can be added.

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