SIG SAUER SWISS ARMS SG552 - Manual (Page 8)

2.1.4. Handguard
The handguard protects the barrel and the gas system
from damage and provides protection from burning.
1 Handguard, upper part
2 Handguard, lower part
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Weapon theory
2.1.3. Bolt
The bolt consists of two main parts:
• Bolt head
• Bolt carrier with gas piston
Bolt head
The bolt head locks the bolt assembly, houses the firing
pin and the extractor and feeds the cartridges to the
chamber.
1 Control cam 4 Firing pin spring
2 Bolt head 5 Firing pin stud
3 Firing pin 6 Locking lug
7 Extractor
Bolt carrier with gas piston
The bolt carrier guides the bolt head, controls the locking
and unlocking by means of the cam, holds the gas piston
and cocks the hammer.
1 Bolt carrier
2 Cam
3 Gas piston
Weapon theory
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illu. 6) Bolt head illu. 7) Bolt carrier with gas piston from left illu. 9) Handguard illu. 8) Bolt carrier with gas piston from right
1 Cocking lug
2 Bolt carrier
3 Bolt handle catch
4 Bolt handle
5 Gas piston
1 2 3 1
1 2 3 5 4 1
2
7 6 5 4 2 3