Mechem NTW-20 (South Africa)

 NTW-20 anti-materiel rifle, with 20mm barrel.

 

 NTW-20 with14.5mm barrel.

 

 NTW-20 disassembled into major components.

	20 mm version	14.5 mm version
Caliber	20 x 83.5 mm MG151	14.5 x 114 mm Russian
Operation	manual bolt action
Barrel length	1000 mm	1220 mm
Weight	26 kg	29 kg
Length	1795 mm	2015 mm
Feed Mechanism	detachable box magazine, 3 rounds
Maximum effective range	1500+ meters	2300+ meters

This rifle was designed in the early to mid 1990s by South African arms designer Tony Neophytou, who also took its part in designing the Neostead combat shotgun. Initial development was under the Aerotek name, and later the Mechem division of the DENEL Group, a major South African arms manufacturer, purchased all rights for this design. In the 1998 South African National Defense Forces adopted this weapon and began to purchase it in some numbers. It is also offered for export sales. The NTW-20 is a long range anti-materiel rifle, developed to reach out across wide plains of South African landscape and to deliver substantial firepower in a relatively compact, two men portable package. It is available in two versions, 20mm and 14.5mm, and could be easily converted from one variant to another by simple replacement of the barrel, bolt, magazine and scope, which will take about 1 minute in the field conditions. These two versions had slightly different applications: 20mm version, built around WW2-era German MG-151 aircraft gun round, can deliver high explosive, fragmentation or incendiary shells with good accuracy, so a relatively "soft" targets could be disabled by the blast and / or fragments. When the long range and armor penetration is an issue, the 14.5mm version comes into the play. It is built around another WW2-era round, Soviet 14.5mm high velocity, armor-piercing cartridge, developed for PTRD and PTRS anti-tank rifles and still widely used in Russian KPV / KPVT heavy machine guns on armored cars and in anti-aircraft mounts. While probably not so accurate as the specially developed .50BMG (12.7x99mm) rifles, mostly due to unavailability of the "match grade" ammunition in the 14.5mm and 20mm, NTW-20 offers significantly more terminal effectiveness than any .50BMG rifle / round combination. 20 mm version could be most effective against targets like parked aircrafts and helicopters, command and communications equipment, radar cabins, fuel dumps, unarmored cars. 14.5 mm version will be more effective against armored personnel carriers or relatively large "soft" targets at extended ranges. Anti-personnel work is by no means a primary task for this huge rifle.

NTW-20 is a manually operated, rotating bolt action rifle. The barrel is locked by the rotating bolt that has 6 lugs. The barrel along with the receiver could recoil inside the chassis frame against combined hydraulic and pneumatic damping system. Large two-chamber muzzle brake also helps to keep recoil at the acceptable level. NTW-20 is fed from the detachable box magazine, that is inserted from the left side and holds 3 rounds. The rifle could be disassembled and carried in two man-portable packs, each weighting about 12 - 15 kg. One pack carries the frame, stock, butt and bipod while the other carries the barrel, sighting equipment
and magazines. NTW-20 is equipped with a 8X magnification, long eye relief telescopic sight on the quick detachable mount. No open sight are fitted by default. The folding bipod is mounted under the receiver, and a non-folding frame above the receiver serves as a carrying handle and a scope protection bracket.

Enfield EM-2 / Rifle, Automatic, caliber .280, Number 9 Mark 1 (Great Britain)

EM-2 assault rifle, officially adopted in Britain as Rifle, Automatic, No.9 Mk.1 but never put into service. Note that the backup sights are in raised position.

 

EM-1 prototype assault rifle.

 

EM-2 disassembled into major components.

 

From let to right: British experimental .280 (7x43mm) cartridge for EM-2; Soviet 7.62x39mm M43; US/NATO 5.56x45mm (.223 Rem); US/NATO 7.62x51mm (.308 Win).

Caliber: 7x43 mm (.280 British)
Action: Gas operated
Overall length: 889 mm
Barrel length: 623 mm
Weight: 3.41 kg with empty magazine
Rate of fire: 450 - 600 rounds per minute (depends on source)
Magazine capacity: 20 rounds

The history of the British EM-2 (Experimental Model-2) assault rifle is interesting and somewhat pitiful story. The EM-2 was born as a result of the experience with small arms, gained during the Second World War. It was obvious that the modern warfare will require the infantry to be armed with light, selective fire weapon with effective range of fire much longer than of submachine gun, but shorter than of conventional semi-automatic or bolt action rifles. This requirement effectively led to the development of the various "intermediate" cartridges. The first power to adopt this concept was the Germany, which issued in limited numbers the selective-fire weapons with intermediate cartridge (7.92x33mm Kurz) since 1942. The Soviet Union was the second to this case, developing its own intermediate cartridge in 1943 and began issuing weapons for it on limited basis since 1944 and on large scale since 1949. The Great Britain also felt the need to replace both Sten submachine guns and SMLE No.4 bolt-action rifles with more modern equipment. The research and experience clearly showed that it is entirely possible to replace both of these weapons with single new weapon, with effective range of fire of no more than 1000 yards and with selective-fire capability. This weapon, of cause, required a new cartridge, which was developed after extensive research and development. This cartridge, an "ideal" from British point of view, was of .280 caliber (7mm) and had a bottlenecked case 43 mm long. The pointed bullet weighted 9.08 g (140 grains) and had muzzle velocity of about 745 m/s (2445 fps). The rough comparison of this round against other most common modern cartridges can be found in the table below. Basically, this cartridge offered significant advantage in effective range and penetration against not only 9x19mm Luger pistol cartridge, but also against 7.92x33mm Kurz German and 7.62x39mm Soviet intermediate cartridges, producing slightly more recoil, which was still significantly less than of .303 British rifle cartridge or latter 7.62x51mm NATO cartridge. This cartridge immediately attracted the attention of the Belgian company Fabrique Nationale, which at the same time worked on the advanced version of their SAFN-49 rifle. Canada also showed significant interest in this cartridge.

Having the "ideal" cartridge on hands, both Britain and Belgium began to develop its own assault rifles. The Belgian part of the story will be covered in the FN FAL article elsewhere on this site, and the British part goes right here. The Royal Small Arms Factory (RSAF) at Enfield Lock began to develop its new assault rifle in the late 1940s. The design team was led by the LTC Edward  Kent-Lemon and Stefan Janson. New prototype rifles were called the EM-1 and EM-2 (Experimental Model 1 and 2) and were of similar layout and dimensions, being different mostly in shape details and controls. Both rifles were of bullpup layout, that means that the magazine and the barrel chamber are located behind the triggerguard and pistol handle. It must be noted that these rifles were not the first ever built in the bullpup layout - I know about al least one bolt action bullpup rifle dated back to post-WW1 period. The EM-2 attracted more attention, being slightly less futuristic in appearance. It was a very well balanced and laid out rifle, with comfortable controls, accurate and reliable. In 1951 the EM-2 rifle was nominally adopted for British service as "Rifle, Automatic, caliber .280, Number 9 Mark 1". Had it been put into service, the British troops could have a first class assault rifle prior to 1960, but due to the NATO standardization issues Britain followed the USA and adopted the overpowered American 7.62x51mm cartridge instead of more promising .280, and EM-2 simply could not be easily rebuilt for this round. So, Brits had to adopt another design, but this is also another story. There's also some rumors that infamous British SA80 / L85 assault rifle, introduced in 1980s, was based on the EM-2 design. It is not true, since the crappy L85 has nothing in common with EM-2 except for general external "bullpup" layout.

The EM-2 rifle is a gas operated, magazine fed, selective fire rifle. It uses gas system with long piston stroke, located above the barrel. The locking system is generally similar to one found in the WW2-period German Gew.43 or in the Soviet Degtyarov DP-27 machine gun (but turned back to front). Bolt locks into the receiver by two flaps, that are pivoted at their rear to extend out of the bolt and into the locking recesses in the receiver walls. Flaps are controlled by the firing pin sleeve, coaxially located inside the hollow bolt, and the sleeve is in turn connected to the gas piston rod by the projection on the rod. The recoil spring is located at the rear part of the gas piston, above the bolt. When gun is fired, the hot power gases cause the gas piston to go to the rear. This movement first causes the firing pin sleeve to retract within the still stationary bolt, causing the locking flaps to be withdrawn from locking recesses and into the bolt. As soon as the bolt is unlocked, it begin to move back against the pressure of the return spring, ejecting the spent case and feeding the fresh round into the chamber on its return into the battery. EM-2 fires from closed bolt all the time. The firing mechanism is striker-fired, with the main spring and the sear located in the bolt. The sear is located at the bottom of the bolt and is operated by the long trigger lever, connected to the trigger. In general, this was somewhat complicated but very dust-proof, reliable and neat design.

The cocking handle is located at the right side of the weapon, on the front part of the gas piston rod, and can be removed when gun is disassembled. The safety switch is located at the front of the triggerguard and is similar in operation to one found in M1 Garand or M14 rifles, and the fire selector is of cross-bolt push-button type, and located above the pistol handle. All controls are easily reachable with firing hand. The furniture (pistol handle and forend) is made from wood, the buttplate is attached to the receiver directly and can be easily removed for field-stripping. EM-2 was fitted with optical sights, mounted on the integral carrying handle as standard. Optical sights were non-adjustable, and range adjustment capability was built into the aiming reticle picture. The emergency (backup) iron sights were also fitted - rear folding peep-hole (diopter) sight was attached to the left side of the carrying handle, and the folding front post sight was mounted on the left side of the gas block.

FN F2000 assault rifle (Belgium)

FN F2000 assault rifle, in standard configuration, with telescope sight

 

FN F2000 assault rifle, in "Tactical" configuration, with Picatinnyrail and back-up open sights

 

FN F2000 assault rifle, with telescope sight and 40mm FN EGLM grenade launcher

 

 FN F2000 assault rifle, in standard configuration, disassembled into major components

 

FN FS2000, a semiautomatic-only version for civilian shooters

 

FN F2000 rifle being fired by Belgian soldier. Note spent case emerging from theport at the front of the rifle

Caliber: 5.56x45 mm NATO
Action: Gas operated, rotating bolt
Overall length: 694 mm
Barrel length: 400 mm
Weight: 3.6 kg empty, in standart configuration; 4.6 kg with 40mm grenade launcher
Magazine capacity: 30 rounds (any NATO / STANAG type magazines)

During the late 1980s and early 1990sfamous Belgian company FN Herstal began the search for its next entry into the assault rifle world. The aim this time was to produce a modern, modular weapon, and this ultimately resulted in the FN F2000 rifle, which was first displayed in public in 2001. The F2000 offers all of the most popular features of the modern assault rifle, such as a compact bullpup layout, completely ambidextrous handling, and a modular design with plenty of options and add-ons already available, which allow the rifle to be “tailored” for any particular mission or tactical situation. For example, for peacekeeping operations F2000 could be fitted with less-lethal M303 underbarrel module, which fires tear gas or marker projectiles using pre-compressed air. On the other hand, the F2000 could be fitted with various 40 mm FN EGLM grenade launchers and a proprietary computerized fire control system, instead of the standard low-magnification optical sights.So far FN F2000 rifle found only few buyers, including Armed forces of Sloveniaand Belgian Special operations forces. Nevertheless, it is one of most promising assault rifles on the market.
 Quite recently FN also introduced a civilian version of F2000, known as FS2000.It has a somewhat longer barrel and is limited to semi-automatic fire. Otherwise it is the same excellent weapon, with great ergonomics and 100% ambidexterity.

The F2000 rifle is a gas operated, rotating bolt, selective-fire weapon, featuring a polymer stock with a bull-pup layout. Itutilizes a short-stroke gas piston and a 7-lug rotating bolt which locks into the barrel extension. The unique feature of the F2000 rifle is its patented front ejection system: the spent cases, extracted from the chamber, travel from the rear part of the gun to the ejection port near the muzzle via a special ejection tube and fall out of the gun at the safe distance from the shooters' face. This is achieved using a special swinging guide, which enters the way of the closing bolt, and directs the spent case, which is held on the bolt face, to the ejection tube, while, at the same time, lower lugs of the bolt are stripping a fresh cartridge from the magazine. The cocking handle is mounted well forward on the left hand side, just above the fore grip, and it can easily be operated with the right hand when the gun is held left-handed. The selector switch is mounted at the bottom of the trigger guard. All of these features combine to make the F2000 the first genuinely ambidextrous bullpup, able to be used with equal ease by right and left handed shooters without requiring any adjustments. In its standard configuration, the F2000 is perfectly balanced around the pistol grip.
 The stock has built-in standard rails on the top of the weapon (for different sights and scopes etc) and a mounting point ahead of trigger guard, where additional modules may be installed (such as grenade launchers, non-lethal modules etc). In the basic configuration, the upper rail mount is fitted with a 1.6X magnification optical sight, and the lower mounting point is covered by a removable handguard. At the current time, the F2000 rifle may be upgraded, depending on the mission, with FN's 40 mm low-velocity grenade launcher (on the lower mount, instead of the handguard), or with M303 non-lethal module; other options are handguards with built-in laser pointers or flashlights. The standard low-magnification combat scope, which has a back-up open sights on its top cover, may be replaced by any other scope onPiatiny-style mount, or with FN's proprietary computerized fire control module with laser rangefinder, for both the rifle and 40 mm grenade launcher.

FN FNC assault rifle (Belgium)

FN FNC rifle of late manufacture (with enlarged triggerguard)

 

 Same rifle, right side view. note the spring-loaded dust cover on the cockinghandle slot

 

FN FNC of earlier manufacture, with butt folded

 

FN FNC Para, with shorter barrel, butt folded and magazine removed.

Caliber: 5.56x45mm NATO
Action: Gas operated, rotating bolt
Overall length: standard model 997 mm (776 mm with folded butt);"Para" model 911 mm / 680 mm
Barrel length: 449 mm (363 mm "Para" model)
Weight with empty magazine: 4.06 kg  (3.81 kg "Para"model)
Magazine capacity: 30 rounds (accept all STANAG-compatible magazines)
Rate of fire: about 700 rounds per minute
Effective range: 450 meters

 

Following the market failure of their previous 5.56mm caliber assault rifle, the CAL, famous Belgian company Fabrique Nationale began to develop the new assault rifle for 5.56mm NATO cartridge in the early 1970s. The final design, called the FNC (Fabrique Nationale Carbine) was produced circa 1978 and was consequently adopted by the Belgian Armed forces. It was also adopted by Sweden and Indonesia,and both those countries purchased the licenses to build more or less modified FNC carbines at their own facilities. Swedish version is known as Bofors AK-5 and Indonesian version is known as Pindad SS1. The FNC also was sold to some police forces around the world, and, in limited numbers for civilians - as a"Sporter" model, limited to semi-automatic mode only. 

The FNC is a sound design which accumulated best features from other famous designs, such as Kalashnikov AK-47,  Colt/Armalite M16,  and others. 

FNC is a gas operated, selective fire, magazine fed weapon. 

The gas drive and rotating bolt of FNC strongly resembles the  AK-47 system, butadapted for more advanced production technologies such as CNC machining and with some modifications. The long stroke gas piston is located above the barrel and is linked to the bolt carrier. Unlike the AK-47, the gas piston rod could be separated from the bolt carrier when gun is disassembled. The gas system featured two-positionsgas regulator (for normal or adverse conditions) and a separate gas cutoff,combined with folding rifle grenade sights. When grenade sights are raised intothe ready position, the gas cutoff automatically blocks the gas supply to the action, allowing for safe launching of rifle grenades. Both gas cutoff and agrenade sight are located on the gas chamber, just behind the front sight. The now common rotating bolt has two massive lugs that locks into the barrelextension. 

The receiver is made from two parts that are linked by two cross-pins. The receiver could be opened for disassembly and maintenance byremoving the rear pin, so the parts could be hinged around the forward pin (which also can be removed to separate receiver parts). Upper receiver is made from stamped steel, the lower receiver, along with magazine housing, is made from aluminum alloy. 

Barrel of the FNC is equipped with flash hider which also served as a rifle grenade launcher. 

FNC is equipped with hooded post front sight and a flip-up,"L" shaped rear diopter sight with 2 settings, for 250 and 400 metersrange. 

The controls of the FNC consist of the 4-positions safety / mode selector switch on the left side of the receiver. Available modes are Safe, Single shot,3-rounds bursts and Full automatic fire. The cocking handle is attached to the bolt carrier at the right side and does reciprocate with the bolt group when gunis fired. The rear part of the cocking handle slot, cut in the upper receiver for cocking handle, is covered by the spring-loaded cover which automatically opens by the handle when it goes back and automatically closes the opening when cocking handle returns forward. 

FNC is equipped with side-folding buttstock, made of steel and covered by plastic. A solid, non-folding plastic butt is available as an option. The pistol handle and the forend are made from plastic. FNC is equipped with sling swivels and can be fitted with special bayonet or with adapter for US M7 knife-bayonet. FNC can be fed from any STANAG (NATO standard) compliantmagazine, and issued with 30 rounds magazines. If required, FNC could be fitted with 4X telescope sight or various IR / night vision sights.

FX-05 Xiuhcoatl assault rifle (Mexico)

Caliber: 5.56x45 mm NATO
Action: Gas operated, rotating bolt
Overall length: 1087 mm (stock extended) or 887 mm (stock folded)
Barrel length: mm
Weight: 3.89 kg empty
Rate of fire: 750 rounds per minute
Magazine capacity: 30 rounds

FX-05 Xiuhcoatl (Fire serpent) assault rifle was developed in Mexico by Directorate of Military Industry (Dirección General Industria Militar Mexicana - DGIM), and was first displayed to public in 2006. The rifle is already in limited production and is issued to Mexican armed forces on limited basis. It is planned to replace older 7.62x51 HK G3 rifles in Mexican service with 5.56mm FX-05 rifles in the coming years. While the FX-05 rifle bears more than passing similarity to the German-made HK G36 rifle, suspicions of the patent infringement from HK were turned down, as the FX-05 does not have any of the patented features of the G36, and have enough internal differences to be considered an original design, although its design is obviously heavily influenced by the German rifle. The FX-05 is currently available in three basic versions - rifle, carbine and short carbine, which differ in barrel length.

The FX-05 Xiuhcoatl assault rifle is gas operated, selective fired weapon. Gas piston is located above the barrel, barrel locking is achieved via multi-lugged rotary bolt. Charging handle can be installed on either side of the weapon. Receiver of the rifle is made from impact-resistant polymer, translucent magazines also made from polymer. Safety / fire mode selector switches are located above the pistol grip, on both sides of the gun. Rifle is equipped with integral Picatinny type rail on the top of receiver, and can be fitted either with removable carrying handle / optical sight unit or with detachable iron sights, with protected front post and diopter-type flip-up rear sights. The shoulder stock is also made from polymer; it folds to the right and can be adjusted for the length of pull. When folded, shoulder stock is located below the ejection port on the right side of the receiver, so the gun can be fired with stock folded.

AICW - Advanced Infantry Combat Weapon (Australia)

2001 concept of the AICW system

2003 concept of the AICW system

2005 testing prototype AICW VX3 weapon

Caliber: 5.56x45mm NATO + 40mm
Action: Gas operated, rotating bolt + Metal Storm patented stacked-projectile caseless
Overall length: 738 mm
Barrel length: n/a
Weigth: 6.48 kg unloaded, w/o sight; 7.85 kg loaded w/o sight (30 5.56mm + 3 40mm rounds); 9.9-9.9 kg loaded w. electronic sight
Rate of fire: 650 rounds per minute (for 5.56mm barrel)
Capacity: 30 rounds (5.56mm) magazine plus 3 40mm rounds in the G/L barrel

The AICW (Advanced Infantry Combat Weapon) is a joint development of the Australian DSTO (Government operated Defence Science and Technology Organisation), and private companies Metal Storm and Tenix Defence. This development has been carried out since the turn of 21st century, closely following the concept of the American XM29 OICW system. Overall, AICW represents the modular weapon system that combines the 5.56mm rifle/carbine copmponent as a host (basic) platform with 40mm multi-shot grenade launcher (G/L) module and multi-purpose electro-optical sighting system, which can be used to fire either rifle or G/L component, and also can provide recon data to external "consumers" such as tactical computers.
The host rifle component of the AICW is the updated Australian-made F88 rifle, which is a license-built Steyr AUG.However, the basic F88 rifle has been extensively modified to accept other elements of the system - for example, receiver has been upgraded to receive the G/L module at the top, and the buttstock has been enlarged to accomodate G/L electronic fire contol module. Other changes include modification to the safety and trigger arrangements - AICW system has a single trigger for both weapon components (5.56 and 40mm), and a three position (safe - rifle - G/L) safety/selector switch at the side of the pistol grip.
The most interesting part of the AICW weapon is the multi-shot Metal Storm 40mm grenade launcher, which looks like a single 40mm G/L barrel but contains three 40mm projectiles stacked one behind the another. These projectiles are launched using the electric ignition impulses, provided by the fire control module built into the buttstock of the host rifle. Since the muzzle velocity of these projectiles is slightly more than usual for 40mm handheld G/L (95m/s instead of 75m/s), host rifle incorporates the recoil reduction buffer, that allows the Metal Storm G/L barrel to recoil against the spring, decreasing the peak recoil impulse.
The top of the receiver hosts the multi-role sights of various type and make. At the AICW VX3 live fire demonstartions that took place in the summer of 2005, AICW prototypes were displayed with ITL Viper multi-purpose rifle sight (that incorporates laser range-finder and digital compas), or with Vinghog Vingsight Fire Control System. At the present time (late 2005) AICW prototypes have not yet fired 40mm grenades with live warheads, nor incorporated an airburst facility. However, it is stated that it is possible to easily adapt most of the existing 40mm grenade warheads to the Metal Storm technology, including air-bursting grenades that are now in development in several countries.

At the present time AICW weapons are available only as the "3rd generation technology demonstartors", that completed first live-fire trials (as a complete system) in the summer of 2005. Current Australian MOD plans state that ADF may start to purchase AICW systems in around 2010-2012.

Steyr Stg.77 AUG assault rifle (Austria)

 Steyr AUG A1 in standard rifle configuration (military green colour)

 

The drawing of the Steyr AUG prototype (circa 1974). From original patent. Notethe open sights instead of the latter built-in telescope sights

 

 Same prototype drawing, major components: barrel group, receiver, plastic housing with magazine and trigger group (from top to bottom)

 

Steyr AUG with M203 40mmgrenade launcher

 

Steyr AUG A1 Carbine (police black colour)

 

 Steyr AUG A2 with Carbine configuration (shorter barrel) and with Picatinny-type rail installed instead of standard telescope sight

 

 Steyr AUG A3 Carbine with 16inch barrel and optional forward grip / tactical flashlight and telescope sight

 

Steyr AUG A3 Carbine with 16inch barrel and special 40mm grenade launcher;grenade launcher sight is attached to the top of removable telescopic riflesight

 

Steyr AUG A3 in Sniper configuration, with heavier and longer 20inch barrel,detachable bipod and long-range telescopic sight

 

Comparison of various AUG barrels, from top to bottom: LMG/heavy barrel with bipod;standard rifle barrel; carbine barrel; SMG barrel.

Click here to see the cross-section ofthe Steyr AUG rifle (58 Kb JPEG, will open in the new window)

Caliber: 5.56mm NATO (.223rem)
Action: Gas operated, rotating bolt
Overall length: 805 mm (with standard 508 mm barrel)
Barrel length: 508 mm (also 350 mm SMG, 407 mm Carbine or 621 mm LMG heavy barrel)
Weight: 3.8 kg unloaded (with standard 508 mm barrel)
Magazines: 30 or 42 rounds box magazines
Rate of fire: 650 rounds per minute
Effective range of fire: 450-500 meters with standard assault rifle barrel

The Steyr AUG (Armee Universal Gewehr - Universal Army Rifle) had been indevelopment since the late 1960s, as a replacement for venerable but obsolete Stg.58 (FN FAL) battle rifles for Austrian army. It was developed by the Austrian Steyr-Daimler-Puch company (now the Steyr-Mannlicher AG & Co KG) in close conjunction with Austrian Army. The major design is attributed to the three men - Horst Wesp, Karl Wagner and Karl Möser, who developed most of the rifle features. From the Austrian Office of Military Technology the project was supervised by the Colonel Walter Stoll. The new rifle has been adopted by the Austrian Army in 1977, as the Stg.77 (Assault rifle, model of 1977), and production began in 1978. Since then, the AUG gained serious popularity, being adopted by the armed forces of Australia, Austria, New Zealand, Oman, Malaysia, Saudi Arabia, Ireland and some others. It also was widely purchased by various security and law enforcement agencies worldwide, including the US Coastal Guard. The Steyr AUG can be considered as the most commercially successful bullpup assault rifle to date. Since the 1997, the Steyr-Mannlicher produced an updated version of the AUG, the AUG A2.
In around 2005, Steyr-Mannlicher introduced the most recent version of AUG, the AUG A3. This version is characterized by addition of four Picatinny-type accessory rails - one at the top of the receiver, and three around the barrel, in front of the receiver - at both sides and below it. Therefore there AUG A3 has no standard / integral sighting equipment; instead, any open, telescope or night vision sights can be installed on the upper rail, using appropriate mountings. Lower rail can be used to mount various attachments like tactical front grips, flash-lights, and a specially designed 40mm grenade launcher. Side rails can be used for equipment like laser-aiming devices.

Some said that the AUG rifle was revolutionary in many respects when it first appeared, but this is not true. In fact, the AUG is a clever combination of the various previously known ideas, assembled into one sound, reliable and aesthetically attractive package. Let's look at this a little closer. Bullpup configuration: The Steyr AUG is not a first military bullpup ever devised. In fact, British Enfield EM-2 and Soviet Korobov TKB-408 bullpup assault rifles precede the AUG by some 25-30 years. The French  FAMAS bullpup also appeared on the scene at the very same time, as the AUG did. Plasticfirearm housing: Another Soviet experimental bullpup design, Korobov TKB-022, had the plastic housing as early as in 1962, and the  FAMAS rifle, again, has this same feature at the same time as AUG did. Telescope sight as a standard: The British  EM-2 bullpup rifle of late 1940s, as well as the experimental Canadian FN FAL prototypes of early 1950s, also featured a low-magnification telescope sights as their prime sighting equipment. A modular design: First systems, consisting of various firearms based on the same receiver and action (automatic rifle, light machine gun, carbine) were originally developed in 1920s in France by Rossignol and in Soviet Russia by Fedorov. Considering all said above, one must agree that the AUG was a logical development of various well known ideas,and a really successful one.

In general, the AUG is known for good ergonomics,decent accuracy and a good reliability.

Technical description.
The Steyr AUG is a gas operated, magazine fed, selective fire rifle of bullpup layout.

AUG is built around the aluminium casting receiver, with steel reinforcement inserts. One such insert is used to provide the locking to the removable barrels and the rotating bolt, thus relieving the receiver from most of the firing stress. Other inserts are used as a bearings for the bolt carrier guide rods.

The AUG uses a short piston stroke, gas operated action, with the gas piston mounted inside the compact gas block, which is fixed to the barrel. The gas cylinder is offset to the right from the barrel. Gas piston has its own return spring, contained inside the gas block. The gas system features a three positions gas regulator, which allows for two open positions (for normal and fouled conditions) and one closed position (for launching the rifle grenades). The gas block also contains a barrel fix / release lock and a front grip hinge. Each barrel has eight lugs, that lock into the steel insert in the receiver, and there's four basic barrel patterns for the AUG: standard rifle barrel is 508 mm (~20 in) long. "Compact" or "Submachine gun" barrel is 350 mm (13.8 in) long, "Carbine" barrel is 407 mm (16 in) long, and the heavy / LMG (light machine gun) barrel is 621 mm (24.4 in) long. On each rifle barrels can be exchanged in the matter of seconds. Each barrel is fitted with the flash hider, and the heavy 621 mm barrel also is fitted with lightweight folding bipods. There's no bayonet lug on Austrian service rifles, but it can be installed if required.

Barrel replacement procedure, as noted above, takes only few seconds (assuming that the shooter has the spare barrel handy). To remove the barrel, one must take off the magazine, and clear the rifle by operating the cocking handle. Then, grasp the barrel by the front grip, push the barrel retaining button at the gas block, and rotate the barrel and pull it out of the rifle. To install a new barrel, simply push the barrel down into the front of the receiver all the way and then rotate it until it locks. The rifle now is ready to be loaded and fired.

The bolt system consists of the bolt carrier, which has two large hollow guide rods, attached to its forward part. The left rod also serves as a link to the charging handle, and the right rod serves as the action rod, which transmits the impulse from the gas piston to the bolt carrier. The rotating bolt has 7 locking lugs, claw extractor and a plunger-type spring loaded ejector. Standard bolt has its extractor on the right side, to facilitate right-side ejection, but the left-side bolts (with mirrored positions of extractor and ejector) are available for those who need left-side ejection. The two return springs are located behind the bolt carrier, around the two string guide rods, that are located inside the bolt carrier guide rods. The cocking handle is located at the left side of the gun and normally does not reciprocate when gun is fired, but it can be solidly engaged to the bolt group if required by depressing the small button on the charging handle. On the latest AUG A2 variant, the charging handle was made folding up and of slightly different shape. The AUG action features a bolt stop device, that holds the bolt group open after the last round of ammunition from the magazine is fired. To release the bolt after the magazine replacement, one must pull the charging handle.

The hammer unit is made as a separate assembly and almost entirely of plastic (including the hammer itself). Only springs and pins are steel. The hammer unit is located in the butt and is linked to the sliding trigger by the dual trigger bars. The safety is of the cross-bolt, push-button type and located above the pistol grip. There's no separate fire mode selector on the AUG rifles. Instead, the trigger itself is used to control the mode of fire. Pulling it half the way back will produce single shots, while the full pull will produce automatic fire. The enlarged triggerguard encloses the whole hand and allows the gun to be fired in winter gloves or mittens.

The standard sighting equipment of the Steyr AUG rifle is the 1.5X telescope sight, with aiming reticle made as a circle. This circle is so dimensioned so its visible inner diameter is equal to the visible height of the standing man at 300 meters range. The adjustment knobs on the sight are used only for zeroing. The sight housing, which is integral to the receiver on the AUG A1 models, also features an emergency backup iron sights at the top of the telescope sight housing. Some early production AUG rifles of A1 pattern were fitted with receivers that had an integral scope mounts. On the AUG A2 models, the standard scope mount can be quickly removed and replaced by the Picatinny-type mounting rail.

The housing of the AUG rifles, integral with the pistol handle and triggerguard, is made from the high impact-resistant polymer, and is usually of green (military) or black (police) colour. The housing has two symmetrical ejection ports, one of which is always covered by the plastic cover. The rubber-coated buttplate is detachable and, when removed, opens the access to the rifle internals, including the hammer unit and the bolt group. The buttplate is held in position by the cross-pin, which also serves a s a rear sling swivel attachment point.

The AUG is fed from the detachable box magazines, that hold 30 (standard rifle) or 42 (light machine gun) rounds. The magazines are made from semi-translucent, strong polymer. The magazine release button is located behind the magazine port and is completely ambidextrous (some said that it is equally NOT comfortable for either hand use).