During the early- to mid-1950s West Germany, like the other NATO countries, faced the need for rearming its army for the newest common 7.62x51mm NATO caliber small arms. Initially Germans preferred the Belgian FN FAL rifle, and adopted it circa 1956 under the designation of G1. Due to obvious reasons Germany wanted to manufacture its military rifles, and attempted to buy a manufacturing license for FAL, but Belgium rejected the deal. So, Germany turned to the another design, available from Spanish company CETME, and known as the CETME mod. A rifle. Germany bought the manufacturing license for CETME rifle and transferred it to the Heckler und Koch (HK) company, located in Oberndorf. HK slightly modified the CETME design, and in 1959 the Bundeswehr (W.Germany Army) finally adopted the CETME / Heckler - Koch rifle as G3 (Gewehr 3 - Rifle, [model] 3). Since that time and until the 1995 the G3 in various modifications served as a general issue shoulder weapon not only for German Armed forces, but also for many other countries. Those include Greece, Iran, Mexico, Norway, Pakistan, Portugal, Sweden, Turkey and many other countries. Total of more than 50 countries during the last 40 years issued the G3 to its forces. The G3 was or still is manufactured in countries like the Greece, Pakistan, Iran, Turkey, Portugal and others. The key reason of high popularity of the G3 is that it is much simpler and cheaper to manufacture, than its major contemporary rivals - Belgian FN FAL and US M14. To the best of my knowledge, the HK itself continued to produce and offer the G3 until the year 2000 or 2001, when it finally disappeared from HK catalogs and web-sites. However, the HK still manufactures a wide variety of firearms, based on the G3 design but of different purposes and calibers, like 9mm MP-5 submachine guns, 5.56mm HK 33 assault rifles, 5.56mm and 7.62mm HK 23 and HK 21 machine guns, PSG1 sniper rifles etc. In general, the HK G3 rifle can be described as one of the best 7.62mm NATO battle / assault rifles - reliable, versatile, controllable, non-expensive and, finally, very popular. For the civilian markets, HK produced the semi-automatic only versions of the G3, initially known as HK 41 and later - as HK 91.
The G3 rifle is a selective fire, magazine fed rifle, built using delayed blowback action, developed by German engineers at Mauser Werke late in the 2nd World War and refined in Spain, at the CETME company. Initial models of the G3 rifle were quite similar to CETME rifles, and even had "CETME" markings on the receivers (until 1961 or so). The roller-delayed blowback action is described under the CETME Rifles, so I will not repeat it here. The G3 is built using as many stamped parts as possible. The receiver is stamped from sheet steel. The trigger unit housing along with pistol handle frame, also are stamped from steel and hinged to the receiver using the cross-pin in the front of the trigger unit, just behind the magazine housing. Earliest G3 rifles also featured stamped handguards and CETME-type flip-up rear diopter sights. In the mid-1960s the initial design was upgraded to the G3A3 and G3A4 configurations. These rifles had ventilated plastic handguards and a drum-type rear diopter sights, marked from 100 to 400 meters. The G3A3 was a fixed butt version, with buttstock made from plastic, and the G3A4 was a telescope butt version, with retractable metallic buttstock with rubber buttplate. Late German production G3A3 and G3A4 models were built using new trigger units, integral with restyled pistol grip and triggerguard, made from plastic. The shortest version of the G3 was the G3KA4, similar to G3A4 but with shortened barrel. Every G3 rifle can be equipped with detachable bipods, claw-type detachable scope mounts. Long-barreled versions can be fitted with bayonet or used to launch rifle grenades from the barrel. Folding cocking handle is located on the special tube above the barrel, at the left side, and does not reciprocate when gun is fired. The safety / fire selector is located above the triggerguard on the left side of the trigger group housing and usually is marked "S - E - F" (Safe - Single shots - Full auto). Latest models could have selectors marked with colored icons.
Markings: `G3 HK serial number month/year of manufacture` on left side of magazine housing. Weapons which have been refurbished will have `HK` and the month/year stamped into yhe right side of the magazine housing.
Safety: A combined safty catch and fire selector is on the left side, above the trigger. In the topmost position (marked `0` or `S`) the weapon is safe; fully down (`F` or `20` gives full automatic fire, while the mid-position (`E` or `1`) gives single shots.
Unloading: Magazine catch on rear of magazine housing. Remove magazine, pull back cocking handle to eject any round in the chamber. Inspect chamber via ejection port , reease cocking handle, press trigger.