The origin of the G3 can be traced back to the final years of World War II when Mauser engineers at the Light Weapon Development Group (Abteilung 37) at Oberndorf am Neckar designed the Maschinenkarabiner Gerät 06 (MKb Gerät 06, "machine carbine device 06") prototype assault rifle chambered for the intermediate 7.92×33mm Kurz cartridge, first with the Gerät 06 model using a roller-locked short recoil mechanism originally adapted from the MG 42 machine gun but with a fixed barrel and conventional gas-actuated piston rod. With careful attention to the mechanical ratios, the gas system could be omitted. The resultant weapon, Gerät 06H (the "H" suffix is an abbreviation for halbverriegelt - "half-locked") was assigned the designation StG 45(M) (Sturmgewehr 45(M) , assault rifle 45) but was not produced in significant numbers and the war ended before the first production rifles were completed.
The German technicians involved in developing the StG 45(M) were taken to work in France at Centre d'Etudes et d'Armement de Mulhouse (CEAM). The StG 45(M) mechanism was modified by Ludwig Vorgrimler and Theodor Löffler at the Mulhouse facility between 1946 and 1949. Three versions were made, chambered in .30 Carbine, 7.92×33 mm Kurz, and the experimental 7.65×35 mm French short cartridge developed by Cartoucherie de Valence in 1948. A 7.5×38 mm cartridge using a partial aluminium bullet was abandoned in 1947. Löffler's design, designated Carabine Mitrailleuse Modèle 1950, was retained for trials among 12 different prototypes designed by CEAM, MAC, and MAS. Engaged in the Indochina War and being the second[clarification needed] NATO contributor, France canceled the adoption of these new weapons for financial reasons.
In 1950, Vorgrimler moved to Spain where he created the LV-50 rifle chambered for the Kurz cartridge and later, the proprietary 7.92×40mm CETME M53 round. At this point, the rifle was renamed the Modelo 2. The Modelo 2 drew the attention of the West German Bundesgrenzschutz (Border Guards), who sought to re-equip the newly formed national defense forces. Not willing to accept a cartridge outside of the NATO specification, the Germans asked CETME to develop a 7.62×51mm version of the rifle. The resulting CETME Model A was chambered for the 7.62×51mm CETME cartridge which was identical in chamber dimensions but had a reduced-power load compared to the 7.62×51mm NATO round. Further development of the rifle with input from H&K produced the CETME Model B which received several modifications, including the ability to fire from a closed bolt in both semi-automatic and automatic firing modes, a new perforated sheet metal handguard (the folding bipod had been the foregrip in previous models), improved ergonomics and a slightly longer barrel with a 22 mm rifle grenade launcher guide. In 1958, this rifle was accepted into service with the Spanish Army as the Modelo 58, using the 7.62×51mm CETME round.
In 1956, the Bundesgrenzschutz canceled their planned procurement of the CETME rifles, adopting the Belgian-made FN FAL as the Gewehr 1 (G1) instead. However, the newly formed West German Army (Bundeswehr) now showed interest and soon purchased a number of CETME rifles (7.62×51mm NATO chambering) for further testing. The CETME, known as the Automatisches Gewehr G3 according to German nomenclature, competed successfully against the Swiss SIG SG 510 (G2) and the American AR-10 (G4) to replace the previously favored G1 rifle. In 1956 the Bundeswehr started extended troop trials with 400 CETME rifles. Heckler & Koch made a number of changes to the CETME rifles. In January 1959, the Bundeswehr officially adopted the technically improved CETME proposal. The West German government wanted the G3 rifle to be produced under license in Germany; purchase of the G1 had previously fallen through over FN's refusal to grant such a license. In the case of the G3, the Dutch firm Nederlandse Wapen en Munitiefabriek (NWM) held production and sales rights to the CETME design outside of Spain. To acquire production rights, the West German government offered NWM contracts to supply the German Air Force (Luftwaffe) with 20mm ammunition. Production of the G3 was then assigned to Rheinmetall and Heckler & Koch. The latter company already had ties to CETME, and had worked to further optimize the CETME rifle for use with the full-power 7.62×51mm NATO cartridge (as opposed to the downgraded CETME variant). In 1969, Rheinmetall gave up production rights to the G3 in exchange for Heckler & Koch's promise not to bid on MG 3 machine gun production. Later in 1977, the West German government ceded ownership of G3 production and sales rights exclusively to Heckler & Koch. After obtaining these rights, Heckler & Koch initially had to pay the government 4 Deutsche Marks per rifle, despite having been awarded the contract by the German government.
Initial production G3 rifles differed substantially from more recent models; early rifles featured closed-type mechanical flip-up sights (with two apertures), a lightweight folding bipod, a stamped sheet steel handguard, a wooden buttstock (in fixed stock models) or a telescopic metal stock. Before delivery to the Bundeswehr, each G3 went through functional checks, zeroing the sight line (Anschießen) and a shooting test at the factory. In the process, five shots were fired at a target at 100 metres (109 yd) with particularly accurate sighting-in ammunition. The 5-shot group could not exceed 120 mm (4.7 in) (1.2 mil/4.13 MOA) diameter. The weapon was modernized during its service life (among other minor modifications it received new sights, a different flash suppressor, and a synthetic handguard and shoulder stock), resulting in the most recent production models, the G3A3 (with a fixed polymer stock) and the G3A4 (telescoping metal stock). The rifle proved successful in the export market, being adopted by the armed forces of over 40 countries. Of that figure, 18 countries undertook domestic production of the G3 under license. Known manufacturers of the weapon included France (MAS), Greece (Hellenic Arms Industry), Iran (Defense Industries Organization), Luxembourg (Luxemburg Defense Technologie), Mexico, Myanmar, Norway (Kongsberg Våpenfabrikk), Pakistan (Pakistan Ordnance Factories), Portugal (FBP), Saudi Arabia (Military Industries Corporation (Saudi Arabia)), Sweden (Husqvarna Vapenfabrik AB and FFV Carl-Gustaf in Eskilstuna), Thailand, Turkey (MKEK) and the United Kingdom (Royal Ordnance).
The Bundeswehr was working on improving their G3 rifles in the 1990s with a brass deflector that deflects spent cartridge cases down and frontwards from the operator and a new polymer pistol-grip/fire-control assembly module that allows better ambidextrous operation of the safety lever when they had their G3 rifles replaced for the Heckler & Koch G36. Currently (2018) hundreds of thousands of G3A3A1, G3A4A1 and G3KA4A1 modernized variants rifles are maintained by Bundeswehr personnel and kept in reserve or are available in military base small arms storages.
A French effort to put the StG 45(M) concept into mass production. Chambered in .30 Carbine.
The G3 is a selective-fire automatic weapon that employs a roller-delayed blowback operating system. The two-piece bolt assembly consists of a breech (bolt head) and bolt carrier. The bolt is held in battery by two sliding cylindrical rollers that engage locking recesses in the barrel extension. The breech is opened when both rollers are compressed inward against camming surfaces driven by the rearward pressure of the expanding gases upon the bolt head. As the rollers move inward, recoil energy is transferred to the locking piece and bolt carrier which begin to withdraw while the bolt head slowly moves rearward in relation to the bolt carrier. As the bolt carrier clears the rollers, pressure in the bore drops to a safe level, the bolt head is caught by the bolt carrier and moves to the rear as one unit, continuing the operating cycle. Based on the geometric relationship arising from the angles of the roller contact surfaces of the locking piece and the barrel extension recesses, the recoil of the bolt head is delayed by a ratio of 4:1 for the 7.62×51mm NATO chambering. Thus during the same period of time, the bolt head carrier moves 4 times faster than the bolt head. This ratio is continued until the locking rollers have been withdrawn from the barrel extension recesses. The bolt features an anti-bounce mechanism that prevents the bolt from bouncing off the barrel's breech surface. The "bolt head locking lever" is a spring-loaded claw mounted on the bolt carrier that grabs the bolt head as the bolt carrier group goes into battery. The lever essentially ratchets into place with friction, providing enough resistance to being re-opened that the bolt carrier does not rebound. The spring-powered claw extractor is also contained inside the bolt while the lever ejector is located inside the trigger housing (actuated by the recoiling bolt).
The G3 is a modular weapon system. Its butt-stock, fore-stock and pistol-grip/fire-control assembly may be changed at will in a variety of configurations (listed below). Simple push-pins hold the components in place and removing them will allow the user to remove and replace parts rapidly. The weapon made extensive use of cost-saving pressed and stamped steel components rather than machined parts and spot welding to connect parts. The stamped sheet metal cocking handle tube and receiver are large exposed parts that are prone to deformation from hard impact as they were designed to be relatively thin to save weight. If dented severely or deep enough during field service, reliability problems due to internal parts movement impairments can occur that put the rifle out of action and can not be field solved by the user. To determine and correct such situations armorers are trained to employ specially designed “GO” and symmetry gauges and straightening mandrels to fairly quickly repair such problems.
The rifle is hammer fired and has a trigger mechanism with a 3-position fire selector switch that is also the manual safety toggle that secures the weapon from accidentally discharging (fire selector in the "E" or "1" position – single fire mode (Einzelfeuer), "F" or "20" – automatic fire (Feuerstoß), "S" or "0" – weapon is safe (Sicher), trigger disabled mechanically). The weapon can be fitted with an optional four-position safety/fire selector group illustrated with pictograms with an ambidextrous selector lever. The additional, fourth selector setting enables a three-round burst mode of fire. The rifle has a relatively high trigger pull of 50–55 N (11.2–12.4 lbf) due to a drop safety requirement. An interchangeable set-trigger pack assembly featuring a trigger stop and less trigger pull is available for the G3SG/1 and other sniping orientated variants.
The original G3 and G3A1 rifle variants had a relatively low iron sight line that consisted of a Klappvisier a "L-type" flip up rear sight and hooded front post. From the G3A2 variant the firearm is equipped with a relatively low iron sight line that consists of a Drehvisier a rotary rear drum and hooded front post. The rear sight is mechanically adjustable for both windage and elevation with the help of tools. This deliberately prevents non-armorers to (re)zero the iron sight line. The rotary drum features an open V-notch (numbered 1) for rapid target acquisition, close range, low light and impaired visibility use and three apertures (numbered 2, 3 and 4) used for: 200–400 metres (219–437 yd) in 100 metres (109 yd) increments for more precise aiming. The 1 V-notch and 2 or 200 metres (219 yd) aperture settings have an identical point of aim. The V-notch and apertures are calibrated for US M80 / German DM111 series or other equivalent 9.5 grams (147 gr) 7.62×51mm NATO ball ammunition. The receiver housing has recesses that work with STANAG claw mounts/HK clamp adapters used to mount day or night aiming optics.
The rifled barrel - four right-hand grooves with a 305 mm (12.0 in) twist rate - terminates with a slotted flash suppressor which can also be used to attach a bayonet or serve as an adapter for launching rifle grenades. From the G3A3 the barrel was free floated from the stock and had polygonal rifling. The barrel chamber is fluted with twelve flutes, which assists in the initial extraction of a spent cartridge casing (since the breech is opened under very high barrel in internal cartridge case pressure).
The G3A3 (A4) uses either steel (260 g) or aluminium (140 g) 20-round double-stacked straight box magazines, or a 50-round drum magazine. H&K developed a prototype plastic disposable magazine in the early 1960s, but it was not adopted as aluminum magazines were just as light and proved more durable, as well as easier to produce.
Standard accessories supplied with the rifle include: a detachable bipod (not included with rifles that have a perforated plastic handguard), sling, cleaning kit and a speed-loading device. Several types of bayonet are available for the G3, but with few exceptions they require an adapter to be inserted into the end of the cocking tube. The most common type features a 63⁄4 inch spear-point blade nearly identical with the M7 bayonet, but with a different grip because of its mounting above the barrel. The weapon can also mount a 40 mm HK79 under-barrel grenade launcher, blank firing adapter, a straight blowback bolt (called a "PT" bolt, lacks rollers) used for firing 7.62×51mm ammunition with plastic bullets, a conversion kit used for training with .22 Long Rifle ammunition and a sound suppressor (that uses standard ammunition).
The G3 served as a basis for many other weapons, among them: the PSG1 and MSG90 precision rifles, the HK11 and HK21 family of light machine guns, a semi-automatic version known as the HK41, a "sporterized" model called the SR9 (designed for the civilian market in countries where the HK91 would not qualify, primarily the US after the 1989 importation restrictions) and the MC51 carbine.
The G3 rifle is or was produced under license in the following countries: Brazil, Iran, France, Greece, Norway, Mexico, Myanmar, Pakistan, Portugal, Saudi Arabia, Sweden and Turkey.
Original G3 variant with older style flip up sights and wooden furniture
German sniper with a modernized G3A3ZF with a STANAG claw mounted Schmidt & Bender 3-12x50 PM II telescopic sight in Afghanistan in 2011
G3TGS: This is simply a G3 with a 40 mm HK79 under-barrel grenade launcher.
TGS stands for Tragbares Granat System ("portable grenade system").
G3TGS: This is simply a G3 with a 40 mm HK79 under-barrel grenade launcher.
TGS stands for Tragbares Granat System ("portable grenade system").
G3A3ZF: This is a rifle issued with a STANAG claw-and rail scope bracket and a Hensoldt Fero Z24 4×24 telescopic sight to be mounted and zeroed by the user. The ZF stands for Zielfernrohr ("Telescopic Sight"). The Hensoldt Fero Z24 4×24 telescope sight for G3 rifle and claw mount assembly were developed for designated marksman use. The Fero Z24 elevation knob features Bullet Drop Compensation (BDC) settings for 100–600 metres (109–656 yd) in 100 metres (109 yd) increments calibrated for 7.62×51mm NATO ball ammunition. The G3A3ZF is otherwise a standard G3A3 that during factory test shooting printed a 5-shot group of 80 millimetres (3.1 in) (0.8 mil/2.75 MOA) diameter or less.
Portuguese Blue Helmets on mission in the Central African Republic at the service of the United Nations HK G3June 2019
Afghanistan: Iranian and Turkish-made G3s
Argentina: Grupo Halcón (Buenos Aires Police Special Operations Group)
Bangladesh: G3A3, G3A4 & G3/SG-1 variants are in service.
Brazil: G3A3, G3A4 and G3SG1 used by special forces. G3A4 and G3SG1 used by police forces.
G3SG1 used by BOPE.
Burkina Faso: French-made G3s
Colombia: Originally in 1975, Heckler and Koch sold to Indumil the manufacturing license for the G3, the MP5 submachine gun, and the HK21 machine gun. Replaced in service by IMI Galil.
Republic of Congo: Used by Cocoye militia during Congo Civil War
Côte d'Ivoire: French-made G3s
Estonia: Uses the Ak4 and AG-3F2 variant.
Gabon: French-made G3s
Germany: Used by the German Army from the 1950s until the mid-1990s as the primary service rifle. Originally to be replaced by the HK G41 and HK G11, post-reunification budget cuts forced the procurement of the HK G36 instead. Large numbers still in storage, and is used in overseas deployments as a designated marksman rifle. Some variants still in use by border guards and police forces.
Greece: The HK G3A3 replaced the American M1 Garand in the late 1970s and manufactured under license by Elliniki Biomihania Oplon (EBO) (now Ellinika Amyntika Systimata (EAS)
Iceland: AG-3 supplied from Norway
Indonesia: TNI-AU (Indonesian Air Force) Special Forces (the Korps Pasukan Khas (Paskhas)) used the G3 as their standard weapon along with the AK-47 since the early 60's during Operation Trikora campaign in Western New Guinea conflict. It was replaced by the Colt M16A3. The G3 is currently used in reserve and training units.
Iran: Manufactured locally by Defense Industries Organization as the G3A6. A bullpup variant is called the G3-A3.
Kurdistan: 8,000 rifles
Latvia: Ak4 variant used by National Guard
Lebanon: French-made G3s
Lithuania: Ak4 variant was used by the Lithuanian Armed Forces and Lithuanian National Defence Volunteer Forces.
Malaysia: The Malaysian Army and Royal Malaysia Police used the G3A4 as their standard weapon along with HK33 since the early 1970s during Communist insurgency in Malaysia (1968–89). The G3/SG-1 used by the sniper teams of both the military and police special forces. It was replaced by the Colt M16A1. The G3/SG-1 is currently used in reserve and paramilitary units
Mauritania – French-made G3s
Mauritius: Former main battle rifle of the Military of Mauritius. Kept in reserve for training. Still in use in limited amount with the anti-riot police.
Mexico: Made under license by Departamento de la Industria Militar, Dirección General de Fábricas de la Defensa, slowly being replaced by the FX-05 Xiuhcoatl
Niger: French-made G3s
Nigeria: Produced under license by Defense Industries Corporation
Norway: Locally produced variant designated AG-3. In service with the Norwegian Army from 1968 to 2008. Largely phased out in the Home Guard (HV) , the last few HV-units to still use it, are set to convert to the HK416 by the end of 2022.
Pakistan: Locally produced by Pakistan Ordnance Factories in G3P4 designation
Portugal: Starting in 1962, it was made in Portugal under license by the Fábrica do Braço de Prata. The Portuguese Marine Corps use a modernized version of the G3 with kit Spuhr.
Saudi Arabia: Made under license by the Military Industries Corporation, General Organization for Military Industries in Alkharj
Sierra Leone: 8,000 received from the UK and Nigeria during the 1970s and the 1980s. Some Iranian-made G3s have also been recovered.
Senegal – French-made G3s
Serbia: Used by Special Forces
South Africa: Used by Special Forces
Sudan: Made under license by Military Industry Corporation as the Dinar
Sweden: Made by three manufacturers, Heckler & Koch in Germany, and under license by Husqvarna Vapenfabrik (1965–70) and Carl Gustaf Gevärsfaktori (1965–80) which was later renamed to Förenade Fabriksverken (FFV) as the Ak 4 (Automatkarbin 4). Two sub-variants are known to exist, one equipped with a rail and Aimpoint sight (Ak4 B) and the other with a 4× magnifying optic, the Hensoldt ZF4×24 (Ak 4OR). It has since been replaced by the Ak 5 (Automatkarbin 5; a modified version of the FN FNC) in the regular army. Ak 4B and Ak 4OR, some times in combination with the M203 grenade launcher, is still in use in Hemvärnet – Nationella skyddsstyrkorna ("Swedish Home Guard"). About 5,000 units will receive a new adjustable stock from 2016. In December 2020, Tidningen Hemvärnet announced that every soldier in the Home Guard will receive the new adjustable stock AK4C variant before the end of 2022.
Syria – G3A3 and G3A4s used as designated marksman rifle by Republican Guard
Turkey: M:French-made G3s by Makina ve Kimya Endüstrisi Kurumu (MKEK) ("Mechanical and Chemical Industry Corporation") as the G3A7 and G3A7A1. A local version called the M65 was produced between 1966 and 1983. During the 1980s it was gradually replaced by the M79, a locally produced version of the HK-33 assault rifle.
Ukraine: Undisclosed quantity of Portuguese-made G3A3/4s sent by Portugal as part of a military package in response to the 2022 Russian invasion of Ukraine.
United Kingdom: Many versions of the G3 were used by the SAS and UKSF like the G3K and MC51. The G3KA4 was designated L100A1 by the British Army.
Yemen: Yemeni Republican guard and the Yemeni Special guard.
Denmark: G3A5, as the Gevær Model 1966 (Gv M/66). Another variant, designated Gevær Model 1975 (Gv M/75) was leased from the German government. All G3s in Danish service are being replaced by the Diemaco C7 (Gv m/95), and Diemaco C8 (Gv m/96).
Georgia: Turkish made G3s used by Special Forces. G3s were also used by Georgian contingent in Kosovo
Portugal: G3A3 and A4 versions. The G3 was the standard-issued rifle of the Portuguese Armed Forces from 1963-2020, manufactured under license by Fábrica de Braço de Prata before it shut down. In 2019, it was announced that it would be replaced by the FN SCAR.The Portuguese Marine Corps still use a modernized version of the G3 with kit Spuhr.
Rhodesia: Portuguese built G3s were used by auxiliary or reserve units of the Rhodesian Security Forces
South Africa: 100,000 FMP-manufactured surplus G3 rifles were bought from Portugal and designated the R2 Rifle. It was the standard-issue rifle of the South African Marine Corps and South African Air Force, as well within the South West African Territorial Force as a substitute for the R1 Rifle (FN FAL) until it was replaced by the R4 assault rifle in the 1980s The rifle's furniture would soon break down in the heat and become loose, so replacement furniture made of a tough polymer was made by Choate Machine & Tool. The forend had recesses for a bipod's legs and the FAL-style polymer buttstock had a rubber buttplate