Sigarms Sig SG 550 SP, SG 551 SP Instructions Manual

							 
 
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							Contents. 
 
1. SAFETY RULES 
 
 
2. WEAPON THEORY  
 
2.1   Weapon description 
2.2   Technical specifications 
2.3   Accessories 
 
 
3. HANDLING 
 
3.1   Important instructions 
3.2   Loading the weapon 
3.3   Unloading 
3.4   Changing the magazine 
3.5   Reloading 
3.6   Filling and coupling of magazines 
3.7   Aiming, firing 
3.8   Adjusting 
3.9   Gas valve position 
3.10 Folding the butt 
3.11 Firing with mittens 
3.12 Use of accessories 
3.13 Field stripping 
3.14 Assembly 
3.15 Function check 
3.16 Procedure in case of faults  
 
 
4. MAINTENANCE 
 
4.1   Cleaning  
 
 
5. FUNCTION 
 
5.1   Weapon function 
 
 
6. APPENDIX 
 
6.1   List of parts 
6.2   Exploded drawing 
 
 
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1. Safety rules 
 
-The shooter should always consider the weapon as loaded and 
ready to fire until he has personally convinced himself of the 
contrary by unloading it. 
 
-Use only commercial grade ammunition. 
 
-Use only ammunition that corresponds to the caliber of the 
weapon. 
 
-During all manipulations point the weapon in a safe direction. 
 
- Never aim the weapon at any object you do not intend to shoot at. 
 
-Do not load the weapon until immediately before use. 
 
-Do not place your finger on the trigger until the target has been 
sighted. 
 
-Unload weapon immediately after shooting is finished. 
 
-Detach bolt and magazine from the weapon prior to transportation. 
 
- Keep weapon and ammunition separately and under lock and key. 
 
-Never leave the weapon unattended and keep it out of the reach of 
children. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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2. WEAPON THEORY 
 
2.1 Weapon description 
 
2.1.1 General 
 
The semiautomatic SIG SG 550/551 SP is a gas operated weapon with 
rotary bolt mechanism. The operation and maintenance of the standard 
version SIG SG 550 and the short version SIG SG 551 are identical. 
 
 
SIG SG 550 SP 
 
Standard version with folding butt, bipod and carrying sling 
 
 
 
SIG assault rifle SG 551 
 
Short version with folding butt. 
 
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							2.1.2 Barrel with receiver and gas system 
The barrel is screwed into the receiver. The muzzle is fitted with a 
flash suppressor. The front sight mount, which is fixed to the barrel, 
contains the gas port, accepts the front sight and gas system and 
also serves as a support for the handguard. 
 
The receiver guides the bolt and houses the locking system. 
The rear sight mount with diopter drum is also mounted on top of 
the receiver. 
 
 
 
 
 
 
 
Barrel with upper receiver and gas system 
 
1. Flash suppressor 
2. Barrel 
3. Gas valve 
4. Front sight 
5. Gas piston 
6. Recoil spring 
7. Gas tube 
8. Rear sight mount 
9. Diopter drum 
10.Receiver casing 
11.Front sight mount 
12.Bayonet lug (on SG 550 only) 
 
 
 
 
 
 
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							2.1.3. Bolt 
 
The bolt consists of two main parts: 
 
-bolt head 
-bolt carrier 
 
 
a. Bolt head 
The bolt head locks the bolt assembly, houses the firing pin and the 
extractor and feeds the cartridge to the chamber. 
 
 
 
 
Bolt head 
 
1. Control cam 
2. Bolt head 
3. Firing pin 
4. Firing pin spring 
5. Firing pin retaining stud 
6. Locking lug 
7. Extractor 
 
 
 
 
 
 
 
 
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							b. Bolt carrier 
 
The bolt carrier guides the bolt head, controls the locking and 
unlocking by means of the cam, connects the bolt to the gas system 
and cocks the hammer. 
 
 
 
Bolt carrier from left 
 
1. Bolt carrier 2. Cam 
      
 
 
 
Bolt carrier from right 
 
1. Cocking lug 
2. Bolt carrier 
3. Bolt handle catch 
4. Bolt handle 
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2.1.4. Handguard and bipod 
 
The handguard protects the barrel and the gas system from damage 
and provides heat protection. The bipod on the SIG SG 550 can be 
used to support the rifle when firing. 
 
 
 
 
 
 
 
 
 
 
Hand guard with bipod 
 
1. Handguard, upper part 
2. Handguard, lower part 
3. Bipod 
 
 
 
 
 
 
 
 
 
 
 
 
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							2.1.5. Trigger assembly and butt 
 
The trigger assembly comprises all the parts required for siring a shot. 
The safety lever on both sides can be set to two positions. 
 
 
 
 
 
 
Position “S” 
 
The weapon is locked in the safe position. 
 
Position “1” 
 
The weapon will fire semi auto. 
 
 
By pivoting the trigger guard to the right or left side, the trigger 
becomes accessible for shooting with mittens. For safety reasons the 
trigger guard must not be shifted until just before firing the weapon, 
and after firing it should be immediately replaced in the normal 
position. 
 
The folding butt is made of high strength synthetic material.  
In the firing position it is held by the butt locking mechanism, and 
when folded it’s held by spring pressure on the handguard. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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Trigger assembly and butt from right 
 
1. Butt 
2. Safety lever 
3. Trigger casing 
4. Magazine catch 
5. Trigger 
6. Pistol grip 
 
 
 
Trigger assembly and butt from left 
 
1. Trigger casing 
2. Bolt catch 
3. Safety lever 
4. Butt 
5. Butt catch 
6. Pistol grip 
7. Trigger guard 
8. Magazine catch 
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