Heckler & Koch G3

Overview:

The G3 is a 7.62mm battle rifle developed in the 1950s by the German armament manufacturer Heckler & Koch GmbH (H&K) in collaboration with the Spanish state-owned design and development agency CETME (Centro de Estudios Técnicos de Materiales Especiales). The G3A3 (A4) is a selective-fire automatic weapon that employs a roller-delayed blowback operating system. The two-piece bolt assembly consists of a breech (bolt head) and bolt carrier. The bolt is held in battery by two sliding cylindrical rollers that engage locking recesses in the barrel extension. The breech is opened when both rollers are compressed inward against camming surfaces driven by the rearward pressure of the expanding gases upon the bolt head. As the rollers move inward, recoil energy is transferred to the locking piece and bolt carrier which begin to withdraw while the bolt head slowly moves rearward in relation to the bolt carrier. As the bolt carrier clears the rollers, pressure in the bore drops to a safe level, the bolt head is caught by the bolt carrer and moves to the rear as one unit, continuing the operating cycle. The bolt also features an anti-bounce mechanism that prevents the bolt from bouncing off the barrel's breech surface. The spring-powered claw extractor is also contained inside the bolt while the lever ejector is located inside the trigger housing (actuated by the recoiling bolt). The rifle is hammer fired and has a trigger mechanism with a 3-position fire selector switch that is also the manual safety toggle that secures the weapon from accidentally discharging (fire selector in the “E” or “1” position – single fire mode ("Einzelfeuer"), “F” or “20” – automatic fire ("Feuerstoß"), “S” or “0” – weapon is safe ("Sicher"), trigger disabled mechanically). The weapon can be fitted with an optional 4-position safety/fire selector group illustrated with pictograms with an ambidextrous selector lever. The additional, fourth selector setting enables a 3-round burst mode of fire. The G3A3 (A4) uses either steel (260 g) or aluminum (140 g) double-stacked straight box magazines. The firearm was equipped with iron sights that consist of a rotary rear drum and hooded front post. The rear sight, mechanically adjustable for both windage and elevation, has an open notch used to fire up to 100 m and three apertures used for: 200, 300 and 400 m. The receiver housing has recesses that work with HK clamp adapters used to mount day or night optics. The rifled barrel (contains 4 right-hand grooves with a 305 mm twist rate) is ended with a slotted flash suppressor which can also be used to attach a bayonet or serve as an adapter for launching rifle grenades. The barrel chamber is fluted, which assists in the initial extraction of a spent cartridge casing (since the breech is opened under very high barrel pressure). Standard accessories supplied with the rifle include: a detachable bipod (not included with rifles that have a perforated plastic handguard), sling, cleaning kit and a speed-loading device. Several types of bayonet are available for the G3, but with few exceptions they require an adapter to be inserted into the end of the cocking tube. The most common type features a 6 3/4 inch spear-point blade nearly identical with the M7 bayonet, but with a different grip because of its mounting above the barrel. The weapon can also mount a 40 mm HK79 under-barrel grenade launcher, blank firing adapter a straight blowback bolt (called a “PT” bolt, lacks rollers) used for firing 7.62x51mm ammunition with plastic bullets, a conversion kit used for training with .22 LR ammunition and a sound suppressor (that uses standard ammunition).

Specifications:

Type

• Battle rifle.

Place of Origin

• West Germany.

Weight

• 4.4 kg (9.7 lb) (G3A3).
• 4.7 kg (10 lb) (G3A4).
• 5.54 kg (12.2 lb) with optic (G3SG/1).
• 4.1 kg (9.0 lb) (G3K).

Length

• 1,025 mm (40.4 in) (G3A3).
• 1,025 mm (40.4 in) stock extended / 840 mm (33.1 in) stock collapsed (G3A4).
• 1,025 mm (40.4 in) (G3SG/1).
• 895 mm (35.2 in) stock extended / 711 mm (28.0 in) stock collapsed (G3K).

Barrel Length

• 450 mm (17.7 in).
• 315 mm (12.4 in) (G3K).

Cartridge

• 7.62x51mm NATO.

Action

• Roller-delayed blowback.

Rate of Fire

• 500-600 rounds/min.

Muzzle Velocity

• 800 m/s (2,625 ft/s).

Effective Range

• 100–400 m sight adjustments.

Feed System

• 20-round detachable box magazine.

Sights

• Rear: rotary diopter.
• Front: hooded post.