Steyr AUG

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 Mannlicher GmbH & Co KG. 
It was adopted by the Austrian Army in 1978 as the StG 77 ("Sturmgewehr 77"), where it replaced the 7.62×51mm NATO StG 58 automatic rifle (a licence-built FN FAL). In production since 1978, 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 semiautomatic). President George H.W. Bush banned the AUG via an executive order under the 1989 Assault Weapon Import Ban. Six years into the ban, AUG buyers gained a reprieve as cosmetic changes to the carbine’s design allowed importation once again. Changes included the pistol grip being changed into a thumbhole stock, and the gun barrel left unthreaded to prevent attachment of flash hiders and suppressors. The ban sunsetted in 2004, and in 2008 Steyr Arms worked with Sabre Defense to produce parts legally in the U.S.
Design details.
The Steyr AUG is a selective-fire, bullpup weapon 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 a rifle, a carbine, a sniper rifle, a sub-machine gun and even an open-bolt squad automatic weapon. The AUG employs a very high level of advanced firearms technology and is made with the extensive use of polymers and aluminium components. It is chambered in 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 9×19mm Parabellum. 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.
Operating mechanism.
The AUG has a rotating bolt that features 7 radial locking lugs and is unlocked by means of 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.
Features.
The AUG comes standard with four magazines, 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.
Muzzle devices and barrel lengths.
A three-pronged, open-type flash suppressors were used on the , and length barrels, whereas the light machine gun barrel received a closed-type ported muzzle device (combination flash suppressor and compensator) and an integral, lightweight folding bipod. The flash suppressors are screwed to the muzzle and internally threaded to take a blank-firing attachment.
Trigger.
The AUG features an Spz-kr type 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.
Ammunition feeding.
The AUG is fed from a translucent, double-column box magazines (molded from a high-strength polymer) with a 30-round capacity and an empty weight of . The light machine gun variant of the AUG uses an extended 42-round magazine. An Argentine variant of the FN FAL chambered in 5.56×45mm NATO cartridge and known as the FALMP III Type 2 also uses the same magazine.
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 ("donut of death") with a basic rangefinder that is designed so that at a 180 cm (5 ft 11in) tall man-size target will completely fill it, giving the shooter an accurate method of estimating range. 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. So when it is set, aiming at the centre of a target will produce a hit at all ranges out to 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, used 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.
Engineering.
The quick-change barrel used in the AUG is cold hammer-forged by GFM-GmbH of Steyr Austria for increased precision and durability, its bore, chamber and certain components of the gas system are chrome-plated (currently nitrided 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"—used for pushing the bolt shut without recocking the rifle. A bolt hold-open device locks the bolt carrier assembly back after the last round has been fired. The newer AUG A3s possess a bolt release button, prior to this development all AUGs and the USR required the cocking handle being retracted to release the bolt group after a new magazine has been inserted. 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.
Modularity.
Stock.
While the AUG is not fully ambidextrous, it can still be configured to be use for left- or right-handed operators by changing the bolt with 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 M16 type STANAG magazines.
Receivers.
The AUG's receiver may also be changed from the standard model with a carrying handle and built-in 1.5× optical sight, to the "T" model receiver which has a universal scope mount to allow for the use of a variety of scopes and sights. The rifle also has several different types of receivers with Picatinny rails. It has proven to be an effective sniper or designated marksman rifle when configured with the light machine gun barrel, the universal scope mount fitted with a Kahles ZF69 6×42 optical sight and the semi-auto-only trigger group.
Firing mechanism.
The AUG's firing mechanism may 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 may desire. It may 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 or squad automatic weapon.
Barrels.
All AUGs are equipped with quick detachable barrels; including compact barrels, carbine barrels, standard rifle-length barrels and light machine gun barrels. Rifles equipped with pattern barrels produced for military purposes are also equipped with bayonet lugs. The and 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 barrel configurations fitted with a fixed, post front-sight used on the standard rifle version with aperture iron sights.
Military adoption.
Australian military.
The Australian Army adopted the Steyr AUG A1 and designated it as the F88 Austeyr. It has a cyclic rate of fire of around 680–850 rounds per minute.
The Australian F88 Austeyr was tested with a new grenade launcher specifically designed for it called the ML40AUS GLA (Grenade Launcher Assembly), one of the lightest underbarrel grenade launchers at less than due to steel, aluminium, and synthetic parts. The GLA is mounted on the rifle's bottom accessory rail with the trigger moving through a removable plug in the trigger guard that allows for operation of the launcher inside of it, moving it further back than other launchers to maintain centre of balance and improve handling. The ML40AUS differs from the M203 by having a side-opening breech to allow for longer grenade rounds, a cross-bolt safety, and a new quadrant sight that mounts to the top rail alongside the rifle's optics. On 21 January 2014 however, Thales announced they had instead selected the Steyr SL40 grenade launcher due to "significant" engineering concerns with the ML40AUS. The SL40 is a derivative of the Steyr GL40 launcher designed specifically for the EF88. It weighs and has a long barrel. Though marginally heavier than the ML40AUS, it has the same attachment, firing mechanism, and control layout.
DSTO Advanced Individual Combat Weapon was an experimental weapon combining the barrel, action and magazine of an F88 Austeyr with an enlarged receiver and stock/body that also incorporates a multiple-shot 40 mm grenade launcher.
Lithgow F90.
The Lithgow F90 was officially adopted by the Australian Defence Force in 2015, it was then designated as the Enhanced F88 (EF88) Austeyr. Its nominal cyclic rate of fire is 740 rounds per minute. The EF88 is part of the LAND 125 Soldier Combat System project and is a significant upgrade to the F88SA2. It was developed and produced at the Australian Defence Industries factory in Lithgow Small Arms Factory, which is now owned by Thales Australia to fulfil current and near future requirements for the Australian Defence Force. It was first displayed to the public in the middle of 2012 and the initial production was scheduled for 2013, its final design and testing ended later on that year. Internally and externally the EF88 is still similar to the Steyr AUG, although it has received many distinctive upgrades and changes. Upgrades include the following:
In June 2012, Thales debuted the F90 at the Eurosatory military exhibition in Paris. Key additions include a bottom rail and a detachable side rail, optional compatibility with STANAG magazines (F90MBR), weight savings over the F88SA2 with a base weight of and the large trigger guard has been reshaped to serve as a vertical foregrip. Thales in partnership with Steyr-Mannlicher are pursuing small arms procurement programs such as the planned replacement of FAMAS used by the French military. Low Rate Initial Production of the F90 began in September 2014. Dasan Manufacturing will be licensed to manufacture them in an effort to bid them to the South Korean military for future replacements of the Daewoo K2. At the Defexpo 2018 convention, MKU has 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.
Lithgow Arms offers the F90 in three different barrel lengths: , , and . The rifle can also be fitted with the SL40 underbarrel grenade launcher.
F90 ATRAX is a planned semi-automatic only variant of the F90 intended for the American civilian market. It was announced by Thales that plans to release the rifle will be discontinued for "ethical reasons."
Austrian military.
The Austrian Army adopted the Steyr AUG in 1978 and designated it as the Sturmgewehr 77 (StG 77).
Irish military.
The Steyr AUG Mod 14 is an AUG A1 upgraded by the Irish Army, which was possible due to the modularity of the rifle. It allowed the Irish Army to make modernisation upgrades. They replaced the original A1 housing/receiver group (with 1.5× optical sight) with an A3 housing/receiver group (with MIL-STD-1913 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 versions. In 2014, they began issuing the rifle to its operational units.
New Zealand military.
The New Zealand Army had adopted the F88 Austeyr and designated it as the IW Steyr (Individual Weapon Steyr). However the New Zealand Army has since adopted the Mars-L and phased out the IW Steyr.
New Zealand variants of the 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.
Variants.
AUG.
The Steyr AUG is a bullpup assault rifle chambered in 5.56×45mm NATO. It was introduced in 1978 and was adopted by the Austrian Army and was designated as the StG 77 in 1978, then it was later adopted by several military agencies around the world.
AUG HBAR.
The Steyr AUG HBAR (Heavy Barreled Automatic Rifle) is a longer heavier-barreled variant of the standard AUG for use as a light machine gun or squad automatic weapon. Its telescoping sight has a 4× magnification rather than the 1.5× magnification of the standard AUG. It can be modified to fire from an open bolt to allow sustained fire. To accomplish this, a modified bolt carrier, striker and trigger mechanism with sear are used.
AUG Para.
The Steyr AUG Para also known as the AUG SMG or AUG 9mm, is a submachine gun variant of the AUG chambered in 9×19mm Parabellum cartridge and has been produced since 1988. It differs from the rifle variants by having a different barrel, bolt and magazine. It is an automatic, blowback-operated model that fires from a closed bolt, and does not use of the rifle's gas system. Unlike the rifle variants, it has a unique 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 standard 25-round box magazines from the Steyr MPi 69 and TMP submachine guns. 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.
Conflicts.
The Steyr AUG has been used in the following conflicts: