Heckler & Koch MSG 90 Binoculars User Manual


 
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Group 6: Magazine
Magazines for 5 rounds are available. Optionally, magazines for 20
rounds can be used.
The magazine is composed of:
1. Magazine housing
2. Follower with follower spring
3. Magazine floor plate
Fig. 10: Magazine 5 rounds
Fig. 11: Magazine 5 rounds, dismantled
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Functioning of the bolt system
The weapon is loaded, cocked and the safety-catch is released.
Squeezing the trigger released the hammer, which strikes against the firing pin.
The cartridge is ignited. The expanding gases drive the bullet forward.
Simultaneously theses gases also exert pressure on the cartridge case. The
forces, which consequently act on the bolt head face, are transmitted partially via
the locking rollers to the receiver, and partially via the locking piece to the bolt
head carrier. The balanced angular ratio of locking piece and barrel extension
results in a delayed recoil motion of the bolt head.
This design concept ensures that the bolt keeps the barrel locked until the
projectile has cleared the muzzle.
Fig. 28: Bolt system in locked position
When the locking roller has fully entered the bolt head recesses, the bolt is able
to slide further to the rear. The cartridge case is ejected and the hammer is
cocked again.
The simultaneously compressed recoil spring returns the bolt to its forward
position, and thereby the next following cartridge is fed from the magazine into
the chamber. The extractor grips the extraction groove at the bottom of the
cartridge.
The sloping surfaces of the locking piece press the locking rollers onto the recoil
surfaces of the barrel extension. The weapon is again ready to fire.
Fig. 29: Bolt system in unlocked position
Stripping the weapon for cleaning