Assault Rifle Development in the 70 Years Since the Sturmgewehr

Assault Rifle Development in the 70 Years Since the Sturmgewehr


ABOVE: April 23, 2006, Staff Sgt. Brad Smith from 3-320th Field Artillery, 101st Airborne Division with his 14.5inch barrel M4, sitting in the middle of the road during a main supply road patrol in Tikrit, shoots at a suspicious object. (U.S. Army photo by Specialist Teddy Wade)

Fallschirmjägergewehr 42 (FG42)

The road leading to the adoption of the modern assault rifle was long and full of potholes. Throughout the years, as the landscape of warfare has changed, concerns, specifications and criteria have evolved significantly. This is the story of how most of the world came to use the modern rifles of today, starting with the design of the FG42.

The Fallschirmjägergewehr 42 was one of the outstanding small arms designs of World War II. Due to a combination of circumstances, no more than 7,000 were produced. This remarkable weapon nearly achieved the impossible feat of being a serviceable select-fire design using the old-style fullpower ammunition (7.92×57mm Mauser). It was one of the notable forerunners of the now popular assault rifles, all of which use lower-power ammunition and are thus more easily controlled.

The FG42 was produced for the German Luftwaffe Fallschirmjäger (paratrooper) and was first used in the dramatic rescue of Mussolini; it later appeared in the beginning of 1944 in Italy, at Monte Cassino and in France at the invasion front. The FG42 is a gas-operated rifle that fires from an open breech when set at automatic fire in order to avoid ‘cook offs’ (premature discharges caused by overheating the round in the chamber), and from a closed breech, to improve accuracy, when set to

One per squad a day/night thermal sight/IR uncooled, weight less than 1,6 kg, restitution eyepiece and integrated video camera transmits images to the system. A wire connection links the weapon to the system. Head-mounted display for indirect observation. Foregrip with control buttons for sights/radio. (Photo: Daniel Linares, Sagem)

The FG42 was one of the first service rifles made in the now popular “straight line” configuration and it had a light bipod and an integral bayonet: all of this in a weapon weighing less than ten pounds (4.55 kg).

The FG42 had a 20 or 10 round magazine that was mounted on the left side of the rifle. Though a side-mounted magazine was common in submachine guns, the larger magazine with heavier ammunition tended to unbalance the weapon. In addition, muzzle rise with automatic fire was substantial and controllable bursts were difficult. This made full-automatic fire only marginally useful. The FG42 used a fairly sophisticated muzzle device that helped with recoil and muzzle flash, but made noise and blast much greater than on similar weapons. Unfortunately, the FG42 was expensive and time-consuming to make and, as a result, it was not favored by the German Oberkommando der Wehrmacht (the armed forces high command). The paratrooper arm of the Luftwaffe declined in importance as the war progressed and the rifle was never properly developed.

FG42 (Fallschirmjägergewehr 42 or “paratrooper rifle 42”) a select-fire battle rifle. Length: 940 mm, barrel: 508 mm, 4 grooves, right hand-hand twist, weight unloaded: 4.50 kg, magazine: 20-round detachable box, cyclic rate: 750 rpm, muzzle velocity: 762 m/s. (Photo: Håland, courtesy of FORSVARSMUSEET – The Norwegian Museum of Defense)

The predecessor to the Automatisches Gewehr G3 – Sturmgewehr 45

The StG 45(M) was a prototype assault rifle developed by Mauser for the Wehrmacht at the end of World War II using an innovative roller-delayed blowback operating system. It fired the 7.92×33mm Kurz (or “Pistolenpatrone” 7.9mm) intermediate cartridge at a cyclic rate of around 450 rpm. But this concept of strong fire, utility and material saving was not produced in any significant numbers and the war ended before the first production rifles were completed. By then it was too late to be taken into action and to have any importance for the war.

After the war, some German technicians involved in developing the StG 45(M) were involved in the development of the new versions and based these on the technical features of the StG 45(M), which then became the CETME Model A and CETME Model B, chambered for the 7.62x51mm, and thereafter the G3. The G3 uses the principle of blowback with delay by rollers, in which the movement of the rollers is controlled by the large firing pin, which forces them into engagement in the receiver sides. Furthermore, it has the ability to fire from a closed bolt in both semi-automatic and automatic firing modes. The 7.62x51mm NATO G3 rifles were modernized during their service life (among other minor modifications, they received new sights, a different flash suppressor, and a synthetic hand guard 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 and was adopted by the armed forces of over 40 countries and in some cases continued to be produced
under license.

The StG 45(M), sometimes referred to as the MP 45(M), was a prototype assault rifle at the end of WWII, using an innovative roller-delayed blowback operating system. It fired the 7.92x33mm Kurz intermediate cartridge at a cyclic rate of around 450 rounds per minute. (Image: Mikesonline2011)

G3 for the Norwegian defense

In 1960, testing began for a new general assault/combat rifle for the Norwegian defense. Due to economic and political reasons, the G3 was finally adopted in 1966 under the designation name AG3. Kongsberg Våpenfabrikk (Kongsberg Arms Factory – now known as KONGSBERG) had already started preparation for the production of parts for 100,000 G3 rifles for the West German army, the “Bundeswehr,” as part of a re-purchase agreement. It was assumed that Norway would go for the G3. Under an agreement with Heckler & Koch, the Kongsberg Arms Factory produced the weapons under license. A total of 253,497 AG3s were delivered within the Norwegian defense forces from February 1967 to
November 1974.

G3A5: ca. 4.7 kg, length: ca. 1,045 mm, barrel: 450 mm, magazine: 20 rounds , rear sight: rotary dioptre; front: hooded post. A serrated thumb groove bolt carrier to aid in silent bolt closure. The G3A3 has a fixed stock and the G3A4 has a telescoping metal stock. (Photo: Rune Wemberg)

After 40 years with a derivative of the Sturmgewehr 45 – new requirements

Due to weight, age, type of ammunition and restricted adaptability, since the mid-1990s the Norwegian military had worked to replace the AG3 with a more modern weapon. The combat missions abroad in the 1990s and 2000s made the situation especially precarious. Most NATO countries had started to use 5.56×45mm NATO ammunition for their assault/combat rifles, while Norway was among the few countries that still had AG3s chambered in 7.62x55mm.

One of the few advantages of 5.56mm ammunition is that it’s lighter than 7.62mm, which means a lot when soldiers are in combat missions and have to carry extra ammo. Shedding weight and bulk from small arms and ammunition could be a lifesaver for an infantry soldier. Mobility and agility are essential for the survivability and effectiveness of ground troops. With estimates of the bulk carried by the average soldier reaching as high as 68 kg (approx. 150 lb.) for a three-day patrol, efforts to shed weight are always welcome. Small arms and ammunition are the most vital and yet the heaviest component of the kit – and the assault rifle is the soldier’s best friend.

This led the Norwegian defense to make small purchases of other types of assault rifles for the forces that operated on special missions abroad. The Norwegian defense had three types of assault rifles in service as of April 2007:

AG3 – 7.62mm, the standard rifle in use in almost all units.

Heckler & Koch G36 – 5.56 mm, in use in Coastal Ranger Command and, to a lesser extent, by soldiers in ISAF service (including the Telemark Battalion).

Colt Canada C8SFW – 5.56 mm, in use by Norwegian Special Forces.

Though 7.62 mm was the initial caliber, 5.56 mm showed up as a future option within NATO and for special and international forces. The main struggle was not a fight about which weapons to use, but which type of ammunition. There was a big debate within the Norwegian defense, but the ultimate decision was to use 5.56 mm.

Outside Meymane in 2006. A Norwegian soldier is with an AG3F1. All versions of the AG3 have the ability to attach a 40 mm HK79 grenade launcher. The 7.62mm powerful bullet fired from his AG3 has an effective firing range of 500m. (Photo: Per Arne Juvang, Forsvarets mediesenter)

Things Take Time

It’s been 33 years since the AG3 rifles went out of production. Norwegian forces, especially those participating in international operations, increasingly and loudly called for a new weapon. The AG3 is too heavy to carry, especially when combined with the rest of a soldier’s kit. The process of choosing a new weapon has been going on for 11 years, hindered by the fact that there are many strong, differing opinions within the military.

The original goal was to decide on a replacement for the AG3 by 2004. Candidates at that time were the C8, G36 and F2000. On October 13, 2005 the MoD reported on the decision to upgrade the AG3 while new weapons were being purchased. The upgrade included new sights, a new type of retractable stock and an RIS foregrip. This announcement gave rise to protests within the Armed Forces and after a period of time that decision was canceled.

In 2006, shooters from all of the armed services tested the candidate weapons and the upgraded AG3. At that time, the C8 SFW version of the C8 was also in service with the Norwegian Coastal Ranger Command and Armed Forces’ Special Command. The HK416 was selected as the new standard rifle for the defense while the HK417 was selected for the infantry sharpshooters (for use against soft targets).

A Norwegian soldier in Afghanistan with his HK416 368mm barrel, equipped with a proprietary accessory rail handguard with MIL-STD 1913 rails on all four sides, for a vertical foregrip, a bipod and Aimpoint CompM4 red dot sight plus 3XMag magnifier. (Photo: Arne Flaaten, Chief photo section, FORSVARETS FORUM)

In April 2007, a defense contract was signed with Heckler & Koch for the delivery of 8,200 HK416 rifles. The weapons would be delivered to the Army, Navy, Air Force and Home Guard task forces. Reserve forces of the Home Guard would retain the AG3.

Also in 2007, 100,000 AG3 were evaluated, and around 2,500 of these were upgraded with Picatinny rails, retractable stocks and new foregrips. The upgraded weapon was named the AG3F2. In October 2011, an initial order for 2.000 Aimpoint CompM4 sights (known as a “tubed” style reflector, or reflex, sight that uses a red LED at the focus of a mirror-type optical collimator to produce an aligned red aiming spot, what is commonly called a red dot sight) and an equivalent number of 3XMag magnifiers and an order of 10,000 Micro T-1 4 MOA was signed, followed in January 2012 by a second order for 12,000 CompM4s and 3,000 3XMags, adding to the approximately 40,000 sights already delivered to the Norwegian army.

Hunter – Killer

The caliber discussion is connected with the assault rifle. After WWII, the NATO-standard weapons became the FN FAL, the G3 and the M14. These three were proven to be excellent. In the late 1960s, the assault rifle concepts in East and West converged again. The U.S. adopted the .223 Remington (5.56x45mm) and in 1980 NATO followed suit. Many Warsaw Pact countries joined in and returned to small-caliber ammunition with the 5.45x39mm (M74) to replace the 7.62x39mm (M43). Adopting the lighter ammo simplified logistics and soldiers could now carry more ammo. Additionally, the new ammo had a straighter trajectory and less recoil, improving accuracy.

Aimpoint CEU “Concealed Engagement Unit” (Photo: Aimpoint)

Meanwhile, based on experiences in Afghanistan with long-distance fighting, the old 7.62x51mm NATO is again being considered as a viable option. In shorter runs this ammo achieves significantly better ballistic performance than similar variations in small and medium calibers. Lethality is one of the major issues and is a combination of situational awareness, firepower, ammunition terminal effect and accurate sights.

Urban warfare has impacted the infantryman’s tools heavily, with compact rifles being the popular choice, as evidenced in America when the U.S. Army shifted from the M16 rifle to the M4 carbine. Reducing dimensions of a conventional rifle means reducing barrel length, which in turn generates a drop in the muzzle velocity (V0), usually with dire consequences on lethality. Guns and ammunition vary in mass (usually measured in grains) and projectile velocity (usually measured in feet per second or meters per second).

The formula for kinetic energy is ½ mv². For example the 7.62x39mm Russian has a mass of 123 Grains (8 grams)and a muzzle velocity (V0) of 2,350 fps (715 meters per second), which works out to 2,045 Joules (16 inch barrel length). 5.56mm NATO, 62 Grains (4 grams), muzzle velocity 2,944 fps (898 meters per second) which works out to 1,613 Joules (14.5 inch barrel length).

CEU behind Aimpoint sight, rotates 260o allowing the operator to look around (right- and left-hand) corners, up staircases, and down tunnels. CEU does not affect the sight’s point of impact and can easily be passed from one operator to another. The optics contained in the CEU gives a true image, not a distorted mirror image. (Photo: Aimpoint)

The M4’s 5.56mm bullet is very light. Its strength is velocity. Despite the mass shootings where they have been used at close range, their real strength is not in close quarters, but in shooting distant targets, especially at ranges of up to 400 meters. Because of its high velocity, it is affected less by wind and gravity. With the ballistics calculator from Winchester, one can compare the 5.56mm bullet with the lower velocity 7.62×39mm bullet (used by the AK-47 and a number of other rifles) that falls more quickly and is pushed further by a crosswind than the M4’s round. A .308 Hunting rifle, mass 0.0095 grams, V0 823 meters per second, works out to 3,217 Joules. The M4 with its round is actually less powerful than most hunting rifles used for animals like deer. Most European countries do have explicit legislation prescribing weapons, calibers and projectile energy to be used when hunting different species of game animals. The 5.56 mm bullet is prohibited due to its pure projectile energy. The M4 is one of the most popular infantry arms in U.S. military history, getting pretty favorable marks from combatants. One of the few complaints has been battlefield lethality, and most of those problems can be attributed to ammunition. Soldiers are having trouble dominating the battlefield past 300 or 400 meters (new ammunition such as the M855A1 EPR, etc. will not be discussed here).

On the other hand, when the M855’s 5.56mm bullet impacts at high velocity, on an opponent not protected by body armor, the bullet yaws in tissue, and the fragmentation creates a rapid transfer of energy which can result in dramatic wounding effects. Statistics mainly concentrate on the number of persons killed, for obvious reasons. But one should not forget the number of wounded persons. For every killed person there are eight wounded. It is difficult to reduce the number of kills drastically because they are often caused by explosion or accidents.

FAMAS delayed blowback rifle. The new variant has a low profile in which the integral sight and carrying handle is replaced by a Picatinny rail. It is the service rifle of the French military. The nearest FAMAS has a EOTech Holographic Weapon Sight. (Photo: Philippe Wodka-Gallien, Sagem)


Compact rifles are now the most popular choice, as evidenced in the U.S. when the army shifted from the M16 rifle to the M4 carbine. Reducing dimensions of a non-bullpup rifle means reducing barrel length, which in return generates a drop in the V0. The bullpup design relocates the action and feed aft of the trigger group, allowing for more compact carrying and better handling form when compared to a traditionally-configured assault rifle.

Additionally, the resulting design is able to retain use for a full length barrel and concentrates the bulk of the weapon at its rear, pressed firmly against the shoulder of the operator. This configuration has been growing in mainstream popularity in recent years, replacing the classic assault rifle form in several modern
military armies.


As weapons evolve, the delicate balance for assault rifle systems between power, weight, recoil and terminal effects will likely shift once again in an attempt to defeat body armor, to match the range of full-power cartridges and to penetrate through wind shields and thin skinned vehicles while still producing good terminal effects.

Norwegian Coastal Ranger Commandos on ski patrol. Shedding weight and bulk from small arms and ammunition could be a lifesaver for an infantry soldier. (Photo: Torbjørn Kjosvold, Forsvarets mediesenter)

STEYR AUG A3 version of the original rifle with a long Picatinny rail at 12 o’clock and two more on the sides. A bolt-catch system was implemented while an AR-15-like magazine release was developed for those used to that system, which is retrofittable to existing rifles. (Photo: Aud Håland)

MSBS 5.56, a Polish assault rifle system based on a common receiver which will allow the potential customer to choose between standard and bullpup rifle. Thermal Aiming Sight, Collimator Aiming Sight, Night Vision Monocular, Helmet Mounted Display. Helmet display as an Off-Axis Observation Device, e.g. “round-the-corner” work. (Photo: Aud Håland)