SIG SAUER SWISS ARMS SG552 - Manual (Page 23)

4.2.3. Greasing and degreasing
Sequence of operations:
1) Unload the weapon
2) Remove the bolt
3) Clean from the chamber down
4.2.4. Daily cleaning
During daily cleaning the weapon should be wiped with a
dry cloth and the metal parts should be lightly lubricated.
4.2.5. Cleaning procedure
• Carry out stripping procedure.
• Remove residual powder from the gas valve,
gas tube and gas piston with weapon cleaning oil.
• Clean the receiver and barrel from the rear.
• Clean the trigger assembly and all remaining
parts of the weapon.
• Clean accessories.
4.2.6. Lubrication procedure
• Lubricate the barrel from the chamber down
and the bolt using oil.
• Lightly oil the valve and gas tube internally
and externally.
• Lightly oil the gas piston and recoil spring.
• Lightly oil the trigger casing.
• Wipe all remaining metal parts with an oil cloth.
Maintenance
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5. Function
5.1. General weapon function of SG 55X
5.1.1. Readiness to fire
At the moment of readiness to fire the bolt is closed and
locked.
• the recoil spring (2) holds the bolt carrier (4)
in the front final position, via the gas piston (1).
• the bolt head (5) is rotated by the control cam (3) of the
bolt carrier (4) in such a way that its locking lugs (8) enga-
ge in the corresponding recesses of the locking piece (9).
• in this position the hammer (7) is cocked and the
release bar (6) is depressed.
5.1.2. Discharging the shot
By pressing the trigger (11) the hammer (7) is released.
The hammer is under pressure of the hammer spring (12)
and strikes the firing pin (10) which, in turn, impacts
against the cartridge primer of the cartridge (P) thus
discharging the shot.
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Function
illu. 56) Weapon loaded illu. 57) Discharging the shot