The Steyr AUG is an Austrian bullpup assault rifle chambered for the 5.56×45mm NATO intermediate cartridge, designed in the 1960s by Steyr-Daimler-Puch, and now manufactured by Steyr Arms GmbH & Co KG. It was adopted by the Austrian Army in 1977 as the StG 77 (Sturmgewehr 77), where it replaced the 7.62×51mm NATO StG 58 automatic rifle. In production since 1977, it is the standard small arm of the Bundesheer and various Austrian federal police units and its variants have also been adopted by the armed forces of dozens of countries, with some using it as a standard-issue service rifle. Steyr AUG importation into the United States began in the 1980s as the AUG/SA (SA denoting semi-automatic). The AUG was banned from importation in 1989 under President George H. W. Bush's executive order restricting the import of foreign-made semiautomatic rifles deemed not to have "a legitimate sporting use." Six years into the ban, AUG buyers gained a reprieve as cosmetic changes to the carbine's design allowed importation once again. Changes included redesigning its pistol grip into a thumbhole stock, and leaving its barrel unthreaded to prevent attachment of a flash hider or suppressor. The Federal Assault Weapons Ban, passed in 1994, further prohibited the manufacture of additional Steyr AUGs or their copies. The ban expired in 2004, and in 2008, Steyr Arms worked with Sabre Defence to produce parts legally in the U.S.

Design details

The Steyr AUG is a selective-fire, bullpup assault rifle with a conventional gas-piston-operated action that fires from a closed bolt. It is designed as a Modular Weapon System that could be quickly configured as an assault rifle, a carbine, a submachine gun and even an open-bolt light machine gun. The AUG is chambered for the 5.56×45mm NATO cartridge and has the standard 1:9 rifling twist that will stabilise both SS109/M855 and M193 rounds. Some nations including Australia, Ireland and New Zealand use a version with a 1:7 twist optimised for the SS109 NATO round. The submachine gun variants are chambered in either 9×19mm Parabellum or .40 S&W. The AUG consists of six interchangeable assemblies: the barrel, receiver with integrated telescopic sight or Picatinny rail, bolt carrier assembly, trigger mechanism, stock and magazine. The AUG employs a very high level of advanced firearms technology and is made with the extensive use of polymers and aluminium components. The AUG comes with a muzzle cap, spare bolt for left-handed shooters, blank-firing adaptor, cleaning kit, sling and either an American M7 or German KCB-77 M1 bayonet.

Operating mechanism

The AUG has a rotating bolt that features 7 radial locking lugs and is unlocked through a pin on the bolt body and a recessed camming guide machined into the bolt carrier. The bolt carrier itself is guided by two guide rods brazed to it and these rods run inside steel bearings in the receiver. The guide rods are hollow and contain the return springs. The bolt also contains a claw extractor that forms the eighth locking lug and a spring-loaded "bump"-type casing ejector. The gas cylinder is offset to the right side of the barrel and works with one of the two guide rods. The AUG uses a short-stroke piston system where the right guide rod serves as the action rod, transmitting the rearward motion of the gas-driven piston to the bolt carrier. The left-hand rod provides retracting handle pressure when connected by the forward assist and can also be utilised as a reamer to remove fouling in the gas cylinder. The firearm uses a 3-position gas valve. The first setting, marked with a small dot, is used for normal operation. The second setting, illustrated with a large dot, indicates fouled conditions. The third, "GR" closed position is used to launch rifle grenades (of the non-bullet trap type). The AUG is hammer-fired and the firing mechanism is contained in the rear of the stock, near the butt, covered by a synthetic rubber shoulder plate. The hammer group is made entirely of plastics except for the springs and pins and is contained in an open-topped plastic box which lies between the magazine and the buttplate. During firing the recoiling bolt group travels over the top of it, resetting the hammer. Since the trigger is located some distance away, it transmits its energy through a sear lever which passes by the side of the magazine. The firing pin is operated by a plastic hammer under pressure from a coil spring.

Engineering

The quick-change barrel used in the AUG is cold hammer-forged for increased precision and durability, its bore, chamber and certain components of the gas system are chrome-plated (currently nitride on US market rifles). The standard rifle-length barrel features 6 right-hand grooves and a rifling twist rate of 228 mm (1:9 in). An external sleeve is shrunk on to the barrel and carries the gas port and cylinder, gas valve and forward grip hinge jaw. There is a short cylinder which contains a piston and its associated return spring. The barrel locks into a steel insert inside the receiver through a system of eight lugs arranged around the chamber end and is equipped with a folding vertical grip that helps to pivot and withdraw the barrel during barrel changes. The most compact of the barrels has a fixed vertical grip. The receiver housing is a steel-reinforced aluminium extrusion finished with a baked enamel coating. It holds the steel bearings for the barrel lugs and the guide rods. The non-reciprocating plastic cocking handle works in a slot on the left side of the receiver and is connected to the bolt carrier's left guide rod. The cocking handle has a forward assist feature—alternatively called a "silent cocking device"—allowing the user to fully push the bolt home without racking the charging handle. A bolt hold-open device locks the bolt carrier back after the last round has been fired. The newer AUG A3s feature a bolt release button; prior to this development, all AUGs and the USR required the user to rack the charging handle to disengage the bolt hold-open after inserting a fresh magazine. Older versions of the AUG can be upgraded to use the newer A3 stock and hammer pack. The rifle's stock is made from fibreglass-reinforced polyamide 66. At the forward end is the pistol grip with an enlarged forward trigger guard completely enclosing the firing hand that allows the rifle to be operated with winter gloves. The trigger is hung permanently on the pistol grip, together with its two operating rods which run in guides past the magazine housing. Behind that is the locking catch for the stock group. Pressing this to the right will separate the receiver and stock. The magazine catch is behind the housing, on the underside of the stock. Above the housing are the two ejector openings, one of which is always covered by a removable strip of plastic. The rear of the stock forms the actual shoulder rest which contains the hammer unit and the end of the bolt path. The butt is closed by an endplate which is held in place by the rear sling swivel. This swivel is attached to a pin which pushes in across the butt and secures the plate. There is a cavity under the buttplate that holds a cleaning kit.

Features

Receivers

The AUG's receiver can be changed from the standard model with a carrying handle and built-in 1.5× optical sight to the 'Special Receiver' which has a STANAG scope mount to allow for the use of a variety of scopes and sights. In later models (A2 and A3), it has several different types of receivers with Picatinny rails.

Sights

The AUG has a 1.5× telescopic sight that is integrated with the receiver casting and is made by Swarovski Optik. It contains a simple black ring reticle. The sight cannot be set to a specific range but can be adjusted for windage and elevation for an initial zero and is designed to be calibrated for 300 m. It also has a backup iron sight with a rear notch and front blade, cast into the top of the aluminium optical sight housing, in case of failure or damage to the primary optical sight. The sight is also equipped with a set of three illuminated dots (one on the front blade and two at the rear) for use in low-level lighting conditions. In order to mount a wide range of optics and accessories, a receiver with a NATO-standard Picatinny rail and detachable carrying handle was also developed and introduced in December 1997. Modern AUGs are equipped with, or can have the Picatinny rail swapped out with, an A3SF 60mm height x3 optic with optional riser and additional crosshair within the "donut" black ring. This specific optic can be piggybacked with other optics on top, as is the norm with Austrian special forces, due to the Picatinny rail included on top of the optic.

Stock

While the AUG is not fully ambidextrous, it can be configured to be used by left- or right-handed operators by changing the bolt to one that has the extractor and ejector on the appropriate side and moving the blanking plate to cover the ejection port not in use. However, there exists also a right-hand-only stock that allows for the use of STANAG magazines.

Ammunition and magazine

The AUG is fed from a detachable proprietary translucent-polymer double-column box magazine with either a 30- or 42-round capacity. Optional NATO stock for STANAG magazine compatibility is also available.

Firing mechanism

The AUG's firing mechanism can also be changed at will, into a variety of configurations, including semi-auto and full-auto, semi-auto and three-round-burst, semi-auto-only, or any other combination that the user desires. It can also be converted into an open-bolt full-auto-only mode of fire, which allows for improved cooling and eliminates cook off problems when the AUG is used as a light machine gun.

Trigger

The AUG features a progressive trigger (pulling the trigger halfway produces semi-automatic fire, pulling the trigger all the way to the rear produces fully automatic fire), and a safety mechanism (cross-bolt, button type) located immediately above the hand grip. In its "safe" position (white dot), the trigger is mechanically disabled; pressing the safety button to the left exposes a red dot and indicates the weapon is ready to fire. Some versions have an ALO or "automatic lockout", a small projection at the base of the trigger. This was first included on the Irish Defence Forces variant of the rifle, and soon after, the Australian Defence Forces variant. In the exposed position, the ALO stops the trigger being squeezed past the semi-automatic position. If needed, the ALO can be pushed up to permit automatic fire.

Barrels and muzzle devices

The AUG features quick detachable barrels and are available in different lengths; including a 382 mm compact length, 417 mm carbine length and 508 mm standard rifle-length. The muzzle device primarily used for these barrel lengths is a three-pronged, open-type flash suppressor. The flash suppressors are screwed to the muzzle and internally threaded to take a blank-firing attachment. AUGs equipped with the 508 mm pattern barrels produced for military purposes are also equipped with bayonet lugs. The 417 mm and 508 mm barrels are capable of launching NATO STANAG type 22 mm rifle grenades from their integral flash hiders without the use of an adapter. AUG barrels can also mount 40 mm M203 or AG36 grenade launchers. Steyr also offers 508 mm barrel configurations fitted with a fixed, post front-sight used on the rifle version with aperture iron sights. A 621 mm heavy barrel with an integrated lightweight folding bipod with a closed-type ported muzzle device (combination of flash suppressor and compensator) is also available, primarily used on the AUG HBAR.

Variants

AUG

The Steyr AUG can also be fitted with either an M203 or AG-C grenade launcher.

AUG HBAR

The Steyr AUG HBAR (Heavy Barrelled Automatic Rifle), also known as the AUG LMG (light machine gun), is essentially an automatic rifle variant of the AUG. It features a heavier and longer 621 mm barrel with an integrated bipod, and the standard AUG receiver with 1.5× magnification scope. It fires from an open bolt to be more suitable for sustained fire, mitigating accidental cook offs. To accomplish this, it uses a modified bolt carrier, striker and trigger mechanism with sear.

AUG 9mm

The Steyr AUG 9mm, also known as the AUG Para, is a submachine gun variant of the AUG chambered for the 9×19mm Parabellum cartridge and has been produced since 1988. It differs from the rifle variants by having a unique 420 mm barrel with six right-hand grooves at a 250 mm (1:9.8 in) rifling twist rate, with a recoil compensator, a slightly different charging handle, and a magazine well adapter enabling the use of Steyr MPi 69 25- and 32-round box magazines. It is blowback-operated and fires from a closed bolt, omitting the original rifle's gas system. A conversion kit used to transform any assault rifle configuration into the submachine gun configuration is also available. The conversion kit consists of a barrel, bolt, adapter insert, and magazine.

Austrian adopted variants

The StG 77 (Sturmgewehr 77) is the designation given by the Austrian Armed Forces when they adopted the Steyr AUG in 1977.

Australian adopted variants

The Australian Defence Force (ADF) adopted a modified Steyr AUG designated as the F88 Austeyr. From the late 1980s, the F88 became the ADF's standard individual weapon replacing the L1A1 SLR and M16A1 in the Australian Army. From the mid 2010s, the Enhanced F88 (EF88) Austeyr replaced the F88.

F88 Austeyr

In 1985, the ADF ordered 67,000 F88 Austeyrs that were manufactured by Australian Defence Industries (now Thales Australia) at their Lithgow Small Arms Factory under licence from Steyr Mannlicher AG. F88 Austeyrs that were fitted with the M203 grenade launcher from the M16A1 had a barrel length of 620 mm. In 2001, the Grenade Launcher Attachment (GLA) replaced the M203 from the M16A1 and also the M79 grenade launcher. The ADF ordered 3167 GLAs. The GLA featured an Inter-bar (armourer attached) interface, a RM Equipment M203PI grenade launcher, and a Knight's Armament quadrant sight assembly to which a Firepoint red dot sight was attached. The bayonet lug and forward vertical grip were removed to fit the Inter-bar. The Advanced Individual Combat Weapon (AICW) developed by the Defence Science and Technology Organisation, Tenix Defence Systems, ADI, NICO and Metal Storm was an experimental F88 Austeyr that incorporated a top barrel for Metal Storm 30 mm rounds.

EF88 Austeyr

The EF88 (Enhanced F88) was developed by Thales Australia for the Australian Defence Force under Project LAND 125 Phase 3C to replace the F88 Austeyr. Thales Australia offers an export version of the EF88 the F90. The EF88 is produced at Thales Australia's Lithgow Arms factory. The contract to develop an improved lighter version of the F88 Austeyr was signed with Thales Australia in December 2011. In September 2014, Thales Australia was awarded a low rate initial production contract after achieving provisional design acceptance. In June 2015, EF88s from the low rate initial production were issued to the Army infantry battalion 1 RAR to trial before the anticipated rollout of the EF88 in 2016. In July 2015, the ADF placed an initial order of 30,000 rifles in two versions a standard rifle with a 20 in barrel and a carbine with a 16 in barrel. In July 2020, a second order was placed for an additional 8,500 rifles. Internally and externally the EF88 is still similar to the Steyr AUG, although it has received many distinctive upgrades and changes. The colour that was chosen was a black-finish compared to the two-tone colour with a "dark khaki undercarriage and a light brown upper" finish of the F88A2s. Upgrades include the following: Thales tested two grenade launchers for the EF88 the Madritsch ML40AUS designed specifically for the EF88 and the Steyr SL40. In January 2014, Thales selected the Steyr SL40 for the EF88 reportedly the ML40AUS had "significant" engineering concerns. The ADF ordered 2,277 SL40s. The SL40 is mounted on the rifle's bottom accessory rail and its trigger protrudes inside the rifle's trigger guard, and uses a Trijicon holographic sight for its sighting system. The SL40 is a derivative of the Steyr GL40 grenade launcher and weighs 1.025 kg and has a 180 mm long barrel. The SL40 does not require a tool to attach it or remove it from the rifle. Within the Australian Defence Force, there has been some discussion about the suitability of the EF88 when compared against variants of the AR-15 platform such as the M4 carbine and SIG MCX. In November 2021, Defence Technology Review reported that Thales Australia, in collaboration with the Australian Army, were developing a next-generation individual weapon in bullpup configuration chambered for the 6.8 mm calibre.

F90

In June 2012, Thales debuted the F90 at the Eurosatory military exhibition in Paris. Lithgow Arms offers the F90 in three different barrel lengths: 360 mm, 407 mm, and 508 mm. The barrels are fixed cold hammer forged, chrome lined and fluted. The rifle has heat-vent cut outs for better heat ventilation. The rifle can also be fitted with the SL40 grenade launcher. Its nominal cyclic rate of fire is 740 rounds per minute. In 2017, Dasan Manufacturing was granted the rights to manufacture the F90, in an effort to bid them to the South Korean military for future replacements of the Daewoo K2. It is marketed by Dasan as the DSR-90. At the Defexpo 2018 convention, MKU gained Indian licensing rights to manufacture the F90 for Indian contracts. In April 2019, the F90CQB variant was planned to be submitted in conjunction with the Kalyani Group for Indian Army requirements on a 5.56 mm NATO carbine. As of April 2020, Bharat Forge is Thales' partner to manufacture the F90. BF will market it to Indian military and law enforcement, and for potential export sales. In 2016, The Firearm Blog reported that a semi-automatic variant of the F90 the Atrax would be available to the US civilian market. In 2018, The Firearm Blog reported that Dasan USA had commenced producing components for the Atrax. In 2019, The Firearm Blog reported that Thales had cancelled the rifle for "ethical reasons." In March 2018, Thales Australia introduced the F90MBR (Modular Bullpup Rifle). It is a successor to the F90, which features STANAG magazine compatibility.

Irish adopted variants

The Steyr AUG 1 entered service with the Irish Defence Forces in 1988. In 2014, the Irish Army began a modernisation programme to upgrade their Steyr AUG A1s, which was possible due to the modularity of the AUG. The result was the Steyr AUG Mod 14, and on the same year the army began issuing the rifle to its operational units. They replaced the original A1 housing/receiver group (with 1.5× optical sight) with an A3 housing/receiver group (with a Picatinny rail on top and right side) allowing a modern optical sight to be fitted. The Trijicon ACOG 4× sight was selected as the new optical sight of the rifle. The rifle features the ALO "automatic lockout" trigger, which can also be found in the Australian and New Zealand variants.

New Zealand adopted variants

The New Zealand Defence Force had adopted the F88 Austeyr ordering 15,000 designated the IW Steyr (Individual Weapon Steyr) that were manufactured in Australia. The IW Steyr entered service in 1988. In 2013, Stuff reported that New Zealand had 13,000 IW Steyrs. In 2015, New Zealand selected the Lewis Machine and Tool Mars-L 5.56mm rifle to replace the IW Steyr and began transitioning to the new rifle in 2017. The variants of the New Zealand IW Steyr were equipped with a single-stage trigger and a two-position safety. The sight added a crosshair to the circle reticule. New Zealand issued both factory and locally modified carbines alongside the full-length rifle variant.

Civilian variants

AUG clones

Conflicts

The Steyr AUG has been used in the following conflicts:

Users

Military

Law enforcement

Non-state