ASSAULT RIFLES

Assault Rifles Assault rifles are primary offensive weapons of modern troops. Today's AR (Assault Rifles) usually have calibres ranging from 5.45mm to 7.62mm, magazine capacity of 20-30 or more rounds, selective full auto and
single shot modes of fire, plus, in some models, 2 or 3 round burst mode. Effective range of fire is some 600 meters or so; effective rate of fire - up to 400-500 rounds per minute in full auto mode. Many assault rifles shown here are, in fact, parts of whole families of assault firearms (from short carbines to light machineguns - Steyr AUG is a good example). Almost all AR's may be equipped with bayonet, optical or Night Vision scope/sight and, some of them, with under barrel grenade launcher or rifle grenade launcher (rifle grenades usually are put on the barrel and fired with a blank cartridge). Today's trends in AR design are wide usage of hardened plastics and lightweight alloys and built-in holographic (collimator) or optical scopes with magnification of 1X to 4-6X (usually 1X or 1.5-3X).
Most of the worlds' recent assault rifles are designed in bull-pup configuration. This means that butt plate is attached directly to the receiver and handle with the trigger placed ahead of the magazine veil. The only major countries that still stick to conventional AR design are Germany (their latest G36 looks a little bit more 'conservative', comparing to Austrian AUG or latest Israeli Tavor), and Russia, where latest ARs are developed in both 'classic' (AN-94, AK-10x) and 'bull-pup' (Groza OC-14) styles.
The history of the concept of the assault rifle started in the early 1910's, when the famous Russian armourer, col. Fedorov designed a small-bore selective-fire rifle with detachable box magazine. Initially, Fedorow designed a brand new small-caliber 6.5mm cartridge for his rifle, but, due to WW1, switched to the Japanese 6.5mm Arisaka load, which was less powerful than the Russian 7.62x54R and available in quantity. This rifle was acquired by the Russian army in small numbers in 1916 and served (in very limited quantities though) with the Russian and Soviet (Red) Army up to 1925. While the design of the selective-fire rifle was not unique for that time, the concept of the "lightened" cartridge, more suitable for full-auto fire, was new. Also, col.Fedorov invented the idea of infantry weapons families (assault rifle, light machinegun, medium machinegun, vehicle and/or aircraft mounted MGs) based on the same actions and receivers.
The next step in this history was made by Germany - in the 1930's, they began research to develop a medium-power cartridge, which would be much lighter than 7.92mm German and easier to fire accurately in full-auto mode. This development led to the 7.92x33mm cartridge (Pistolenpatrone 7.92mm). The Germans developed some weapons designs for this load, including the MP43 and Stg.44, but this was too late for Germany... Further development of such designs was made by German engineers in Spain, and later in West Germany, and led to the HK G3/G41 family of battle&assault rifles.
The United States also put in some effort to this idea, and before WW2 developed a special less-than-medium powered cartridge .30Carbine and a rifle for this cartridge - a so-called "baby-Garand" in semi-auto M1 and selective-fire M2.
But the largest stride forward was made by the USSR, when, in 1943, the Soviet Army adopted a new cartridge - the 7.62x39mm medium-power load. In 1945 , the Soviet Army adopted the semi-auto SKS rifle in this chambering, and, in 1947 - the AK (known for the West as AK-47). The AK was Worlds' first successful assault rifle, and one of the most widely used. The Last major step on this road was made by US again - in the late 1950's, the US Army adopted a new (for the US) concept of military selective-fire rifle using a small-caliber cartridge. The first of such weapons adopted was the Armalite AR15/Colt M16, designed by Eugene Stoner. This adoption lately set the new world trend for small-caliber (5.45-5.56mm / .22in.) high-velocity cartridges.
All further research and development, such as ceaseless ammunition, multiple-bullet or sabot cartridges, etc., still haven't produced any practical results.