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Heckler and Koch 7.62 mm G3 rifle
Development
The Heckler and Koch G3 has been the service rifle of the German Army since 1959. It remains in
production, not only in Germany, but in other countries where licensed production has been negotiated.
Many of these producer nations also have marketing rights, so G3 rifles may be encountered almost
anywhere throughout the world, often without Heckler and Koch authorisation or knowledge.
Description
The G3 receiver is a steel pressing, grooved on each side to guide the bolt and seat the backplate, and
carrying the barrel. Above the barrel a tubular extension, welded on to the receiver, houses the cocking
lever and the forward extension of the bolt. The cocking lever runs in a slot cut in the left side of this
tubular housing and can be held in the open position by a transverse recess. The barrel is screw-threaded
at the muzzle with a serrated collar to engage the retaining spring of the flash eliminator or blank-firing
attachment. The rifling is orthodox and the chamber carries 12 longitudinal flutes extending back from
the lead to 6 mm from the chamber face.
The bolt is shaped with a long forward overhang which is hollow and takes the return spring. It
extends into the tube above the barrel. The bolt head carrier has long bearing surfaces on each side
which slide in the grooves in the sides of the receiver. The bolt head carries two rollers which project on
each side and are forced out by the inclined front faces of a `locking piece'. When out, the rollers engage
in recesses in the barrel extension. The bolt head and locking piece seat in the bolt head carrier and are
held by the bolt head locking lever to prevent bounce on chambering the cartridge. The trigger
mechanism fits into the grip assembly, secured to the receiver by a locking pin.
When the trigger is squeezed the hammer flies forward driving the firing pin through the hollow
locking piece to fire the cap. The pressure generated in the chamber forces the cartridge case rearwards
and exerts a force on the breech face which drives the bolt head back. Before the bolt head can go back,
the rollers must be driven inwards. The rollers, which are carried in the bolt head, are pushed back and
the angle of the recesses in the barrel extension is such that the rollers are forced inwards against the
inclined planes on the front of the locking piece. In turn this inward force drives the locking piece back
and with it the bolt head carrier. The angle of the locking piece face is such that the velocity ratio
between bolt head carrier and bolt head is 4:1. Thus, while the rollers are moving backwards and
inwards the bolt head carrier is travelling back four times as far as the breech face.
As the carrier moves back the bolt head locking lever is disengaged. After the bolt face has moved
back a little over a millimetre, the rollers are clear of the recesses in the barrel extension, the entire bolt
is blown back by the residual pressure with the bolt head and bolt carrier maintaining their relative
displacement of about 5 mm. The bolt head carrier cocks the hammer and compresses the return spring.
The cartridge case, held by the extractor, hits the ejector arm and is thrown out to the right. The rear end
of the carrier hits the buffer. The buffer action, assisted by the return spring, drives the bolt carrier
forward. The front face of the bolt head strips a cartridge from the magazine and chambers it. The
extractor springs over the extraction groove of the cartridge and the bolt head comes to rest. The locking
piece and bolt carrier then close up the gap of 5 mm and the rollers are pushed out into the recesses of
the barrel extension. The bolt head locking lever engages the bolt head shoulder, thus preventing
bounce. The weapon is then ready to be fired again.
A blank-firing attachment may be screwed on the muzzle instead of the flash eliminator. The
attachment consists of an open-ended cylinder with a cross-bolt which closes the opening entirely. A
groove is cut across the bolt so that by rotating the bolt the amount of gas escaping can be regulated to
produce correct functioning of the rifle. This device has a dull chromium-plated finish to prevent
confusion with the flash hider.
A special bolt marked `PT' replaces the normal bolt and is used for firing plastic training ammunition.
This works on pure blowback and has no delay rollers. It is not suitable for use with service
ammunition. The normal magazine is used for plastic ammunition.
To conserve ammunition and allow troops to train in confined and built-up areas, a subcalibre
training device is available. It consists of a subcalibre tube with a special bolt and magazine. The
ammunition used is 5.6 × 16 mm (0.22 Long Rifle). The subcalibre tube is inserted from the breech and
locked with a spring ring. In addition, the tube is secured by a bolt on the magazine engaging in the end
of the chamber face of the tube. The extractor enters a groove in the chamber face. The bolt assembly
carries out the normal functions of chambering, supporting, firing, extracting and cocking the hammer.
The magazine for 20 5.6 × 16 mm cartridges fits into the normal G3 magazine.
A silencer may be screwed to the barrel in place of the flash hider and serves to reduce the muzzle
report. It will fit all Heckler and Koch rifles with rifle grenade guides.
The use of subsonic ammunition is not recommended, in view of its reduced performance and the
need for a special sight. The principal purpose of this silencer is for it to be used on firing ranges in
order to reduce noise disturbance both for firers and local residents.
Variants
The standard rifle, in production since 1964, is known as the G3A3 and has a plastic butt-stock and
plastic handguard.
When a telescopic sight is fitted to this rifle it is called the G3A3ZF.
When the plastic butt-stock is replaced by a retractable butt it is called the G3A4.
The G3K model is a short assault rifle with the retractable butt fitted as standard. This, combined with
a shorter (322 mm) barrel, reduces the minimum overall length to 720 mm, or 900 mm with the butt
extended. The weight, without magazine, is reduced to 4.4 kg.
The G3A5 was a version produced for sale to Denmark.
The G3A6 is the Heckler and Koch designation given to a version developed for licence production
in Iran. This version is still in production in Iran at the Mosalsalsasi Weapons Factory. Rifles are
produced in two versions, the G3 A1 with a fixed butt and the G3 A1-1 with a retractable butt.
The G3A7 is the Heckler and Koch designation given to a version developed for licence production
in Turkey by MKEK. These are produced in two versions, the G3-A3 with a fixed butt and the G3-A4
with a retractable butt.
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