swissarmsSAN Swiss Arms AG

Semi-automatic rifles SG 550 SP and SG 551 SPCaliber 5,56 mm (.223)

Edition 1.01

Manual

1

Safety warnings

2

Safety warnings

13 commandments of firearms safety

1 ALWAYS treat every gun as if it were loaded.

2 ALWAYS be sure the barrel is clearof any obstruction.

3 ALWAYS be sure of your backstop,what lies beyond and the safety of bystanders before you shoot.

4 ALWAYS use clean, dry, original fac-tory-made ammunition of the propertype and caliber for your gun.

5 ALWAYS wear ear protection andsafety glasses when shooting.

6 ALWAYS carry your gun so that youcan control the direction of the muzzleif you fall or stumble.

7 NEVER shoot at a flat surface or water.

8 DO NOT leave an unattended gunloaded. Guns and ammunition shouldbe stored separately, locked if possible,beyond the reach of children and careless adults.

9 NEVER allow your firearm to beused by anyone who has not read andunderstood this instruction and Safetymanual.

Dangerous Weapons

PISTOLS, REVOLVERS, SHOTGUNS andRIFLES are classified as FIREARMS orDANGEROUS WEAPONS and are soldby us with the specific understandingthat we are not responsible in anymanner whatsoever for their safehandling or resale under local laws andregulations. SAN Swiss Arms shall notbe responsible in any manner whatso-ever for malfunctioning of the firearm,for physical injury or for property dam-age resulting in whole or in part from(1) criminal or negligent discharge, (2)improper or careless handling, (3) un-authorized modifications, (4) defective,improper, hand-Ioaded, or reloadedammunition, (5) corrosion, (6) neglect,or (7) other influences beyond our di-rect and immediate control. This limita-tion applies regardless of whether lia-bility is asserted on the basis of con-tract, negligence or strict liability (in-cluding any failure to warn). Under nocircumstance shall SAN Swiss Arms beliable for incidental or consequentialdamages, such as loss of use of prop-erty, commercial loss and loss of earn-ings or profits.

SAFETY WARNING

The safety warnings in this booklet areimportant. By understanding the dan-gers inherent in the use of any firearm,and by taking the precautions de-scribed herein, you can enjoy completesafety in the use of your Rifle. Failureto heed any of these warnings may re-sult in serious injury to you or others,as well as severe damage to the fire-arm or other property.

3

Safety warnings

10 DO NOT point any gun, loaded orunloaded, at any undesired target.

11 NEVER fire your rifle near an animalunless it is trained to accept the noise:an animal’s startled reaction could in-jure it or cause an accident.

12 NEVER drink alcoholic beverages ortake drugs before or during shooting,as your vision and judgement could beseriously impaired making your gunhandling unsafe.

13 ALWAYS seek a doctor’s advice ifyou are taking medication, to be sureyou are fit to shoot and handle yourrifle safely.

Protect your eyes and ears

Always wear adequate safety glassesand ear plugs or “earmuff” type pro-tectors whenever you are shooting. Al-ways make certain that persons closeto you are similarly protected. Unprotected eyes may be injured bypowder gas, carbon residue, lubricant,metallic particles or similar debriswhich may emanate occasionally fromany firearm in normal use. Without ear protection, repeated ex-posure to shooting noise may lead tocumulative, permanent hearing loss.

Ammunition

1 Use only high quality, original fac-tory-manufactured ammunition. Donot use cartridges that are dirty, wet,corroded, bent, or damaged. Do not oilcartridges. Do not spray aerosol-typelubricants, preservatives, or cleaners di-rectly onto cartridges or where excessspray may flow into contact with car-tridges. Lubricant or other foreignmatter on cartridges can cause potenti-ally dangerous ammunition malfunc-tions. Use only ammunition of the cali-ber for which your firearm is chamber-ed. The proper caliber is permanentlyengraved on your firearm; never at-tempt to use ammunition of any othercaliber.

2 The use of reloaded, “remanufactur-ed”, hand-Ioaded, or other non-stan-dard ammunition voids all warranties.Reloading is a science and improperlyloaded ammunition can be extremelydangerous. Severe damage to the fire-arm and serious injury to the shooteror to others may result. Always use am-munition that complies with the indus-try performance standards establishedby the Sporting Arms and AmmunitionManufacturers’ Institute, Inc. of theUnited States (SAAMI).

3 Firearms may be severely damagedand serious injury to the shooter or toothers may result from any conditioncausing excessive pressure inside thechamber or barrel during firing. Excess-ive pressure can be caused by obstruc-tions in the barrel, propellant powderoverloads, or by the use of incorrectcartridges or defectively assembled car-tridges. In addition, the use of a dirty,corroded, or damaged cartridge canlead to a burst cartridge case and con-sequent damage to the firearm andpersonal injury from the sudden escapeof high-pressure propellant gas withinthe firearm’s mechanism.

4 Immediately stop shooting andcheck the barrel for a possible obstruc-tion whenever:– You have difficulty in, or feel un-

usual resistance in, chambering acartridge, or

– A cartridge misfires (does not gooff), or

– The mechanism fails to extract a fired cartridge case, or

– Unburned grains of propellant powder are discovered spilled in themechanism, or

– A shot sounds weak or abnormal.In such cases it is possible that a bulletis lodged part way down the barrel. Firing a subsequent bullet into the ob-structed barrel can wreck the firearmand cause serious injury to the shooteror to bystanders.

4

Safety warnings

9 Use lubricants sparingly on the moving parts of your firearm. Avoid excessive spraying of any aerosol guncare product, especially where it mayget on ammunition. All lubricants andaerosol spray lubricants in particular,can penetrate cartridge primers andcause misfires. Some highly penetrativelubricants can also migrate inside car-tridge cases and cause deterioration ofthe propellant powder; on firing, thepowder may not ignite. If only the primer ignites, there is danger that thebullet may become lodged in the bar-rel.

IF A BULLET IS IN THE BORE, DO NOTATTEMPT TO SHOOT IT OUT BY USINGANOTHER CARTRIDGE, OR BY BLOW-ING IT OUT WITH A BLANK OR ONEFROM WHICH THE BULLET HAS BEENREMOVED: SUCH TECHNIQUES CANGENERATE EXCESSIVE PRESSURE,WRECK THE FIREARM AND CAUSE SERIOUS PERSONAL INJURY.If the bullet can be removed with acleaning rod, clean any unburned pow-der grains from the bore, chamber, andmechanism before resuming shooting.If the bullet cannot be dislodged bytapping it with a cleaning rod, take thefirearm to a gunsmith.

7 Dirt, corrosion, or other foreignmatter on a cartridge can impede com-plete chambering and may cause thecartridge case to burst upon firing. Thesame is true of cartridges which are damaged or deformed.

8 Do not oil cartridges, and be sure towipe the chamber clean of any oil orpreservative before commencing toshoot. Oil interferes with the frictionbetween cartridge case and chamber-wall that is necessary for safe function-ing, and subjects the firearm to stresssimilar to that imposed by excessivepressure.

5 Bullets can become lodged in thebarrel:– If the cartridge has been improperly

loaded without propellant powder,or if the powder fails to ignite, (igni-tion of the cartridge primer alonewill push the bullet out of the car-tridge case, but usually does not generate sufficient energy to expelthe bullet completely from the bar-rel), or

– If the bullet is not properly seatedtightly in the cartridge case. Whensuch a cartridge is extracted fromthe chamber without being fired,the bullet may be left behind in thebore at the point where the riflingbegins. Subsequent chambering ofanother cartridge may push the firstbullet further into the bore.

6 If there is any reason to suspect thata bullet is obstructing the barrel, im-mediately unload the firearm and lookthrough the bore. It is not sufficient tomerely look in the chamber. A bulletmay be lodged some distance downthe barrel where it cannot easily beseen.

5

Safety warnings

NEVER completely trust any safety

1 Your firearm comes equipped withan effective, well-designed safety de-vice. HOWEVER, NEVER RELY COM-PLETELY ON ANY SAFETY MECHANISM.It is NOT a substitute for cautious gunhandling. NO safety, however positiveor well-designed, should be totally trusted. Like all mechanical devices, thesafety is subject to breakage or malfunc-tion and can be adversely affected bywear, abuse, dirt, corrosion, incorrectassembly, improper adjustment or re-pair, or lack of maintenance. Moreover,there is no such thing as a safety whichis “child-proof” or which can complete-ly prevent accidental discharge fromimproper usage, carelessness, or “horse-play”. The best safety mechanism isyour own good sense; USE IT! Alwayshandle your firearm as though you ex-pect the safety NOT to work!

2 While handling any firearm, do notallow it to point at any part of your body or at another person. No harmwill result if you obey this rule, even ifan accidental discharge occurs.

3 Never carry this rifle with a car-tridge in the chamber and the trigger-cocked.

4 Always keep your finger off thetrigger and point the muzzle in a safedirection when operating the gun re-lease.

Loading

1 Always make sure the muzzle ispointed in a safe direction!

2 Never attempt to load or unloadany firearm inside a vehicle, buildingor other confined space (except a prop-erly constructed shooting range). En-closed areas frequently offer no com-pletely safe direction to point the fire-arm; if an accidental discharge occurs,there is great risk of injury or propertydamage.

3 Before loading, always clean allgrease and oil from the bore andchamber, and check to be certain thatno obstruction is in the barrel. Any for-eign matter in the barrel could resultin a bulged or burst barrel or other damage to the firearm, and could cause serious injury to the shooter orto others.

Firing

1 Keep the muzzle pointed in a safedirection and your finger away fromthe trigger when cocking any firearm.

2 Never carry about or leave unat-tended any firearm which is cockedand ready to fire! When cocked, it willfire from slight pressure on the trigger.An accidental discharge could easily result if you fall or drop the firearm, orif the firearm is struck or disturbed bysomeone or something.

3 Never fire any firearm with yourfinger, hand, face, or other part of yourbody over or adjacent to the ejectionport, or in any position where you maybe struck by reciprocating movementof the breech. Both the ejection ofempty cartridge cases and the move-ment of the breech are part of the nor-mal operating cycle of firearms, andpose no safety hazard to the shooter ifthe firearm is held in a normal grip andfired at arm’s length.

6

Safety warnings

Maintenance

All firearms require periodic mainten-ance and inspection which may reveala need for adjustment or repair. Haveyour firearm checked by a competentgunsmith annually even if it seems tobe working well, since breakage, im-proper functioning or corrosion of some components may not be appar-ent from external examination. If younotice any mechanical malfunction, doNOT continue to use the firearm. UN-LOAD the firearm and take it to a com-petent gunsmith immediately for athorough examination. Similarly, if water, sand, or other foreign matterenters the internal mechanism, im-mediately dismantle the firearm for acomplete and thorough cleaning. Fail-ure to keep your firearm clean and inproper working order can lead to a po-tentially dangerous condition and anaccident causing serious bodily injuryor property damage may result.

Unloading

1 Always make sure the muzzle ispointed in a safe direction!

2 Remember to clear the chamber after the magazine has been removed.

3 Never assume that any gun is un-loaded until you have personallychecked it!

4 After every shooting practice, makea final check to be certain the firearmis unloaded before leaving the range.

Transport and storage

When transporting your firearm to andfrom shooting activities, keep it un-loaded for your safety and for the safety of others.

When storing your firearm, keep it sep-arated from ammunition, under lockand key if possible, and out of thereach of children and other inexperi-enced or unauthorized persons.

4 Never allow other persons to standbeside you where they might be struckby an ejected cartridge case. The case ishot, and may be ejected with sufficientforce to cause a burn or cut or injure anunprotected eye. Make certain there isa clear, unobstructed path for safe ejec-tion of the fired case. Remember, thecase may bounce off a hard object nearby and strike you or someone else.

5 If, while shooting, your firearm de-velops a mechanical malfunction orbinding, or “spits” powder gas, or if acartridge primer is punctured or a car-tridge case is bulged or ruptured, or ifthe report on firing does not soundquite right, STOP SHOOTING IMMEDI-ATELY! It may be dangerous to contin-ue. UNLOAD THE FIREARM – do NOTtry “one more shot”. Take the firearmand the ammunition to a gunsmith forexamination.

6 While shooting any firearm, an un-fired cartridge or fired cartridge casemay occasionally become jammed be-tween the slide and the barrel. Clearthe jam as follows, WHILE KEEPINGTHE MUZZLE POINTED IN A SAFE DI-RECTION: Remove the magazine, thenpull back the slide and lock it to the rear by pushing up the slide release.The jammed cartridge or case now canbe removed by shaking it out or bypicking it out with the fingers.

7

Safety warnings

Care and cleaning

1 Your firearm is delivered factorypackaged and preserved with a lightcoating of protective grease and oils.Before loading make certain that allpacking grease and oil has been clean-ed from the bore and exposed mechan-ism.

2 Before you begin to disassembleyour firearm for cleaning, alwaysdouble-check to make sure it is unload-ed!

3 After cleaning always check to besure that no cleaning patch or otherobstruction remains in the bore orchamber!

Parts

Our Service Department maintains afull complement of replacement parts.Even though most gunsmiths have theknowledge, training and ability to make the necessary repairs to your fire-arm, the skill and workmanship of anyparticular gunsmith is totally beyondour control. Should your firearm everrequire service, we strongly recom-mend that you return it to SIGARMSINC. Follow the instructions outlinedbelow. Remember, unauthorized ad-justments of parts replacement can void your warranty.

A firearm is a precision instrument andsome replacement parts will require in-dividual fitting to insure correct oper-ation.

A wrong part, improper fitting or in-correct mechanical adjustment may re-sult in an unsafe condition or danger-ous malfunction, damage to the fire-arm, or possible serious injury to theshooter or to others. IF ANY PART ISORDERED WITHOUT RETURNING THEFIREARM TO SIGARMS INC, the custom-er bears full responsibility for ensuringthat the part supplied is correct for hisparticular firearm and is properly in-stalled and fitted by a qualified gun-smith. SAN Swiss Arms and SIGARMSINC CANNOT BE RESPONSIBLE FOR THEFUNCTIONING OF ANY FIREARM INWHICH REPLACEMENT PARTS ARE IN-STALLED BY OTHERS.

SIGARMS INC service policy

Before shipment your firearm was carefully inspected and test fired in or-der to ensure that it conformed to ourspecifications and standards. Shouldyour firearm require adjustment, repairor refinishing, we strongly recommendthat you return it to SIGARMS INC forfactory service.

8

Safety warnings

5 Be sure to enclose a letter statingserial number, caliber and barrel lengthof your firearm. Also state nature oftrouble experienced or work required.Merely stating “defective” or “repairas necessary” is inadequate informa-tion. Be specific and enclose copies ofany previous correspondence. Work(otherthan warranty repair) will bear aminimum labor charge of $ 10.00.

6 FIREARMS MUST BE SHIPPED UN-LOADED. Double-check the chamber ofyour firearm before shipping. If fire-arms are sent to SIGARMS INC in a loaded condition, we are required bylaw to notify the Federal authorities.

7 DO NOT include telescopic sights,custom stocks, slings, or other access-ories with any firearm shipped to us.

To return any firearm to us for adjust-ment, repair or refinishing, please fol-low these suggestions to expedite ser-vice:

1 Only Federally licensed dealers mayship handguns via the U.S. Mail. Hand-guns mailed by individuals are confis-cated by the Post Office.

2 Federal law permits you to returnyour firearm to the manufacturer forservice via common carriers such asUnited Parcel Service (UPS) or, if yourfirearm is a rifle or shotgun, by U.S.Mail. However, state and local firearmslaws vary greatly; you should consultyour local prosecuting attorney regard-ing any restrictive laws in your jurisdic-tion regarding your shipment or re-ceipt of firearms. With the above inmind, it is strongly recommended thatany firearm sent to us for repair besent through a Federally licensed deal-er.

3 All firearms must be shipped to usprepaid. WE WILL NOT ACCEPTCOLLECT SHIPMENTS.

4 Firearms returned for repair shouldbe addressed to:SIGARMS INCIndustrial DriveExeter, NH 03833

If there is any question regarding theperformance of your firearm, pleasewrite to SIGARMS INC. Service Depart-ment fully describing all circumstancesand conditions involved. If our ServiceDepartment makes the determinationthat your firearm requires factory ser-vice, you will be so advised and will begiven instructions for the most expedi-tious handling of your shipment.

Our Service Department will give yourfirearm a complete inspection, andevaluate the problem(s) specified inyour letter.lf the work required is notcovered under the terms of our “Lim-ited Warranty” (a copy is enclosed withyour firearm), you will receive an ac-tual cost quotation, not an estimate.Any repair work must be authorized byyou, and no work will be done withoutyour express approval.

Semi-automatic rifles SG 550 SP and SG 551 SP

Caliber 5.56mm (.223)

Manual

9

10

Page

1. Safety rules 3

2. Weapon theory 4

2.1. Weapon description 4

2.2. Technical specifications 12

2.3 Accessories 13

3. Handling 15

3.1. Important instructions 15

3.2. Loading the weapon 15

3.3. Unloading 16

3.4. Changing the magazine 16

3.5. Reloading 16

3.6. Filling and coupling of magazines 17

3.7. Aiming, firing 18

3.8. Adjusting 19

3.9. Gas valve position 20

3.10. Folding the butt 21

Page

3.11. Firing with mittens 21

3.12. Use of accessories 22

3.13. Field stripping 23

3.14. Assembly 26

3.15. Function check 28

3.16. Procedure in case of faults 29

4. Maintenance 30

4.1. Cleaning 30

5. Function 31

5.1 Weapon function 31

6. Appendix 38

6.1. List of parts 38

6.2. Exploded drawing 40

Contents

11

Safety rules

– Do not place your finger on the trigger until the target has beensighted.

– Unload weapon immediately aftershooting is finished.

– Detach bolt and magazine from theweapon prior to transportation.

– Keep weapon and ammunition separately and under lock and key.

– Never leave the weapon unattendedand keep it out of the reach of children.

I. Safety rules

– The shooter should always considerthe weapon as loaded and ready tofire until he has personally con-vinced himself of the contrary by un-loading it.

– Use only commercial grade ammuni-tion.

– Use only ammunition that corre-sponds to the caliber of the weap-on.

– During all manipulations point theweapon in a safe direction.

– Never aim the weapon at any objectyou do not intend to shoot at.

– Do not load the weapon until im-mediately before use.

12

MusterseiteWeapon theory

2. Weapon theory

2.1. Weapon description

2.1.1. General

The semi-automatic SG 550/551 SP is agas operated weapon with rotary boltmechanism. The operation and main-tenance of the standard version SG 550SP and the short version SG 551 SP areidentical.

SG 550 SP (1)

Standard version with folding butt, bipod and carrying sling.

SG 551 (2)

Short version with folding butt.

1

2

13

MusterseiteWeapon theory

1 2 3 4 5 6 7 8 9

11 10

Barrel with receiver and gas system.

1 Flash suppressor2 Barrel3 Gas valve4 Front sight5 Gas piston6 Recoil spring7 Gas tube8 Rear sight mount9 Diopter drum

10 Receiver casing11 Front sight mount

2.1.2. Barrel with receiver and gas system

The barrel is screwed into the receiver.The muzzle is fitted with a flash sup-pressor. The front sight mount, which isfixed to the barrel, contains the gasport, accepts the front sight and gas system and also serves as a support forthe handguard.The receiver guides the bolt and housesthe locking system. The rear sight mount with diopter drum are also mounted on top of the receiver.

2.1.3. Bolt

The bolt consists of two main parts:– Bolt head– Bolt carrier

Bolt head

The bolt head locks the bolt assembly,houses the firing pin and the extractorand feeds the cartridges to the cham-ber.

Bolt head

1 Control cam2 Bolt head3 Firing pin4 Firing pin spring5 Firing pin stud6 Locking lug7 Extractor

14

Weapon theory

1 2 3

7 6 5 4

Bolt carrier

The bolt carrier guides the bolt head,controls the locking and unlocking bymeans of the cam, connects the bolt tothe gas system and cocks the hammer.

Bolt carrier from left

1 Bolt carrier2 Cam

1

2

15

Weapon theory

2.1.4. Handguard and bipod

The handguard protects the barrel andthe gas system from damage and pro-vides protection from burning. The bi-pod on the SG 550 SP can be used tosupport the rifle when firing.

Handguard with bipod

1 Handguard, upper part2 Handguard, lower part3 Bipod

Bolt carrier from right

1 Cocking lug2 Bolt carrier3 Bolt handle catch4 Bolt handle

1

2

3

2.1.5. Trigger assembly and butt

The trigger assembly comprises all theparts required for firing a shot. The safety lever on both sides can be set totwo positions:

Position “S” = The weapon is lockedin the safe position.

Position “1” = The weapon will firesemi auto.

By pivoting the trigger guard to theright or left side the trigger becomesaccessible for shooting with mittens.For safety reasons the trigger guardmust not be shifted until just before firing the weapon, and after firing itshould be immediately replaced in thenormal position.The folding butt is made of highstrength synthetic material. In the firing position it is held by the buttlocking mechanism, and when folded itis held by spring pressure on the hand-guard.

Trigger assembly and butt from right

1 Butt2 Safety lever3 Trigger casing4 Magazine catch5 Trigger6 Pistol grip

16

Weapon theory

1 2 3

6 5 4

17

Weapon theory

Trigger assembly and butt from left

1 Trigger casing2 Bolt catch3 Safety lever4 Butt5 Butt catch6 Pistol grip7 Trigger guard8 Magazine catch

1 2 3 4

8 7 6 5

2.1.6. Sights mechanism

The sights mechanism comprise the re-ar sight and foresight.The rear sight is made up of the:– Rear sight mount– Diopter drum– Windage correction screw– Elevation correction screw

The diopter drum can be set to positi-ons “1”, “2”, “3” and “4”, correspon-ding to firing ranges 1OO m, 2OO m,3OO m and 4OO m. The positions mar-ked in white correspond to aimingpoint = point of impact. The red “3”position corresponds to aiming point“black 6” at 3OOm.

Sighting position “1” is designed forimmediate firing, and two luminousdots are fitted laterally for aiming atnight.

The foresight with tunnel is fixed to itsmount with the foresight screw. A fol-ding foresight is provided for use atnight with the night sights on the diop-ter drum.

Rearsight assembly

1 Receiver casing2 Rear sight mount3 Elevation correction screw4 Rear sight drum5 Night sight6 Windage correction screw

Front sight

1 Front sight tunnel2 Front sight3 Night front sight4 Front sight screw

18

Weapon theory

1 2 3 4 5 61

2

3

4

19

Weapon theory

Magazine, dismantled

1 Feeder2 Magazine spring3 Magazine floorplate catch4 Magazine floorplate5 Magazine coupling lugs6 Magazine casing

2.1.7. Magazine

The magazine is transparent and has acapacity of twenty rounds. On either side of the casing there is a mechanismwhich allows several magazines to beconnected if required.

1 2 3

6 5 4

20

Weapon theory

2.2. Technical specifications

SG 550 SP SG 551 SP Dimensions

Caliber inches .223 .223Total length inches 39.29 34.53Length with butt folded inches 30.39 25.63

Barrel

Barrel length inches 20.78 16.02Number of grooves 6 6Rifling:SG 550-1 SP/SG 551-1 SP: right inches 10 10SG 550-2 SP/SG 551-2 SP: right inches 7 7

Sights

Type diopter sightsSight base inches 21.26 18.34Range adjustment m 100 to 400

yards 110 to 440

Weight

Weapon incl. empty magazine lb 9.03 7.49Empty twenty-round magazine oz 3.35 3.35Empty thirty-round magazine oz 3.87 3.87Loaded twenty-round magazine oz 11.99 11.99Loaded thirty-round magazine oz 16.75 16.75 Subject to change without notice.

21

Technical specifications

Loading toolCarrlying sling in woven nylon withtwo hooks, an adjustment clip and abuckle

2.3. Accessories

Every SG 550/551 SP has the followingaccessories:– carrying sling– loading aid– cleaning kit

22

Accessories

Cleaning kit

1 Weapon grease tube2 Cleaning rod handle3 Grease brush4 Barrel brush5 Cleaning rod sections6 Extension rod with ferrule7 Cleaning jag8 Cleaning brush9 Cleaning brush

10 Gas tube brush11 Chamber cleaning tool12 Barrel inspection mirror

1

12

11

10

2

34

5

67

8

9

23

Accessories

1 Safety lever2 Bolt3 Magazine4 Trigger guard

3. Handling

3.1. Important instructions

– Before manipulating the weapon,make sure it is safe and that the trig-ger guard is put in vertical position.

– Use only commercial grade ammuni-tion.

– Use only ammunition that corre-sponds to the caliber of the weapon.

– During all manipulations point theweapon in a safe direction.

– Do not place your finger on the trig-ger until the target has been sight-ed.

– Do not load the weapon until im-mediately before use.

– Unload weapon immediately aftershooting is finished.

– Detach bolt and magazine from theweapon prior to transportation.

3.2. Loading the weapon

1. Put the safety lever to position “S”.2. Swing the trigger guard into the

vertical position.3. Insert the magazine and check that

it is properly seated by pressing for-ward.

4. Carry out loading movement (pullthe bolt handle fully back and let itfly forward).

1 2

4

3

Inserting the magazine

3.3. Unloading

1. Put safety lever to position “S”.2. Swing trigger guard into vertical po-

sition.3. Remove magazine by pressing ma-

gazine catch.4. Carry out loading movement, with

bolt retracted, check for emptychamber.

5. Switch safety lever to “1”, pull trig-ger (with weapon pointing at tar-get), switch safety lever to “S”.

Check the chamber

1 Chamber

3.4. Changing the magazine

1. Put the safety lever to position “S”.2. Swing trigger guard into vertical

position.3. Remove magazine.4. Insert loaded magazine and check

that it is properly seated by pushingforward.

3.5. Reloading1. Put the safety lever to position “S”.2. Swing trigger guard into vertical

position.3. Remove empty magazine by press-

ing magazine catch.4. Insert loaded magazine and check

that it is properly seated by pushingforward.

5. Push the bolt catch up or pull backthe bolt handle slightly and allowthe bolt to fly forward.

24

Handling

1

Push the bolt catch up

25

Handling

3.6.2. Coupling of magazines

1. Hold magazine vertically.2. With the floorplate of the second or

third magazine pointing to the rear,firstly connect the upper lugs, thenrotate forward and connect lowerlugs.

3.6. Filling and coupling of magazines

3.6.1. Filling the magazine

1. Place loading tool on magazine.2. Insert the ammunition clip and press

cartridges into magazine.3. Remove loading tool.

Loading the cartridqes into the magazine by means of the loadingtool

Coupling of magazines

Sight picture point of aim Bull’s eye 6 o’clock with sight setting“red 3” at 300 m

26

Handling

3.7. Aiming, firing

To aim, align the eye, diopter or battlesight, foresight and target. When usingthe diopter, ensure that the peripheryof the foresight tunnel and the diopteraperture are concentric.

At all ranges, the foresight should beaimed at the center of the target. Firing is therefore to point of aim.

Sight picture night sight

27

Handling

Rear sight

1 Receiver casing2 Windage correction screw3 Rear sight drum4 Elevation correction screw

Elevation

High shots are corrected by turning theelevation correction screw to the left.Low shots are corrected by turning thescrew to the right.

Correction symbol on rear sight (correction of elevation)

3.8. Adjusting

To correct for elevation and windage,the corresponding correction screw isturned with a screwdriver.

By rotating the elevation correction screw and the windage correction screw by one click, the average point ofimpact in the vertical respectively thehorizontal axis is displaced by approxi-mately 0.15 ‰.

1 2 3 4

Windage

Shots to the right are corrected by turning the windage correction screwto the left.Shots to the left are corrected by turning the screw to the right.

Correction symbol on rear sight (correction of windage)

Firing- (average point of impactrange correction per notch)

SG 550 SG 551

100 m 1,5 cm 1,8 cm200 m 3,0 cm 3,6 cm300 m 4,5 cm 5,4 cm400 m 6,0 cm 7,2 cm

To adjust for elevation or windage thecorresponding correction screw is turn-ed with a screwdriver.

3.9. Gas valve position

With the SG 550/551 SP, the gas volumerequired for the function of the weap-on can be controlled by the gas valve.

Position I (Rib of gas valve in verticalposition)

Under normal conditions, firing is effected in this position.

Gas valve in position I

Position II (Rib of gas valve in slantingposition)

When cycling or ejection problems areencountered due to heavy fouling oricing-up, the gas valve is to be turnedclockwise as far as the stop. In this posi-tion, a larger gas quantity acts on thegas piston.

The adjustment of the gas valve is effected manually, and, in case of a hotor heavily fouled weapon, by means ofa cartridge or auxiliary aid.

Firing with gas valve in position II is anexception. As soon as the weaponworks, the gas valve must be turnedback to position I, otherwise the recoilis intensified and the weapon is unne-cessarily stressed.

Gas valve in position II

28

Handling

29

Handling

3.11. Firing with mittens

For firing with mittens the trigger guard can be pivoted to the left orright. For safety reasons the trigger guard must be placed in the verticalposition before carrying out any mani-pulations.

Trigger guard folded

1 Trigger casing2 Trigger guard

3.10. Folding the butt

Thumb in the butt catch and fold thebutt so that it registers with the hand-guard under spring pressure.

Butt folded

1 Butt catch2 Butt

1 2

30

Handling

Sling hooked to foresight mount.

Sling hooked to rearsight mount

Sling attachment to the butt

Fix the taut sling

3.12. Use of accessories

3.12.1. Carrying sling

One end of the sling hooks into the lugon the foresight mount; the other endis attached to the butt.

To fix the taut sling, use the clip.

To maintain a taut sling, slip the clipover the sling strap.

31

Handling

3.13. Field stripping

1. Unload weapon.2. Unlock carrying sling.3. Press the rear trigger casing stud

from both sides and withdraw itfrom the stud head side as far as thestop.

4. Lay the weapon on its left side andswing out the trigger assembly.

5. Withdraw the front trigger casingstud as described in point 3 and re-move the trigger assembly.

6. Press down the bolt handle catchand remove the bolt handle.

7. Use the bolt handle to push the boltto the rear, remove the bolt fromthe receiver.

8. Twist the bolt head to remove itfrom the bolt carrier.

Remove bolt handle

Remove the trigger housing stud Push bolt to the rear, using bolt handle

Remove bolt head

1. Push in2. Rotate

Remove bolt head

1.

2.

Handling

32

15. Remove the firing pin:– Hold the bolt head against a firm

surface in such a way that the fi-ring pin is completely pressed intothe bolt head.

– Remove the retention stud using aknife-edge and extract the firing pin and spring.

11. Press in the gas-valve catch, removethe valve by simultaneously rotat-ing it and pulling it forward.

12. Push the gas piston and recoilspring forward, reaching throughthe ejection port, and extract themfrom the front.

13. Press down the gas-valve catch androtate the gas tube through 90° sothat the notch on the headpiece lieson the barrel.

14. Pull the gas tube out from the frontend.

9. Pull lower handguard to the rearand remove, swing out the bipodlegs and remove laterally

10. Lift upper handguard at the rearand remove at the front sight mount.

Lift off lower handguard

Remove bipod carrier from the handguard

Remove gas valve

Push in gas piston

Remove firing pin

33

Handling

16. Dismantle the magazine:– Press in the retention lug of the

magazine floorplate with thethick end of the firing pin. Pullthe magazine floorplate out fromthe rear.

– Pull out the floorplate catch alongwith the spring and the follower.

Dismantle magazine

SG 550 SP dismantled

34

Handling

4. Insert the piston with recoil spring:– Insert the piston, with its reten-

tion notch slide facing against thebarrel, into the gas tube.

– Check with the forefinger that thegas piston moves freely in the tube.

Correct position of detention notch

3. Install the gas tube:– Slip the gas tube (flange notch

pointing downwards) through thebore of the foresight mount andinsert the end into the corre-sponding opening in the receiver.

– Press the gas tube against the foresight mount and turn itthrough 90° to the right so thatthe retention stud of the gas valveregisters in the flange.

3.14. Assembly

The weapon should always be reas-sembled in the reverse order of stripp-ing:

1. Assemble magazine.2. Insert firing pin:

– Slip the firing pin and spring intothe bolt head. Ensure that thenotch is correctly placed to acceptthe retention stud.

– Push the firing pin into the bolthead and secure it with the reten-tion stud as soon as the notch isflush with the bore.

Insert firing pin

Correct position of the notch

Check correct position with index finger

35

Handling

5. Install the gas valve:– With the notch for the retention

stud facing downwards in theflange of the gas tube.

– Press in the catch and turn the gasvalve to the right up to positon I.

– Check that the gas valve catch hasregistered.

Install gas valve

6. Install the upperhandguard.7. Attach the bipod.8. Install lower handguard.9. Assemble bolt head and carrier.

10. Insert bolt assembly:– Slide bolt head completely to the

front by pressing firing pin.– lide bolt into receiver casing.

Inserting the bolt assembly

11. Insert the bolt handle into its slot inthe bolt carrier and check that ithas registered with the catch.

12. Install trigger casing:– Ensure that the holes in the front

trigger casing stud overlap.– Press the trigger casing stud

through as far as the stop.– Tilt up the trigger casing and fix

with rear trigger casing stud.13. The function check should be

carried out in accordance with Sec-tion 3.15.

36

Handling

4. Insert empty magazine and checkfirm seating.

5. Bolt catch.

a) Carry out loading movement: thebolt must be retained in the rearposition.

b) Thumb up the bolt catch: the boltmust run forward.

6. Check engagement of folded butt,pull the trigger and put the weaponon safe.

3.15. Function check

The function check described below isto be made after every stripping.

1. Unload per Section 3.3.

2. Make sure that bolt handle is en-gaged in correct position.

3. Functions:

a) Safety lever set to “S”, carry outloading movement, pull the trig-ger: the hammer must not trip,the trigger must be blocked.

b) Safety lever set to “1”, pull thetrigger and hold it: the hammermust trip.Carry out a loading movementwith trigger being pulled: thehammer must not trip.Release the trigger and pull itagain: the hammer must trip.

c) Loading movement: Safety leveron “1”: verify serveral times thatthere is a discernible pressurepoint.

37

Handling

3.16. Procedure in case of malfunction

Whenever an SG 550/551 SP no longerworks due to a malfunction, proceed asfollows.

– Carry out loading movement.– Continue firing.

If the weapon does not fire:

– Insert a fresh magazine.– Loading action.– Continue firing.

If the weapon still does not fire:

– Put weapon on safe.– Remove magazine.– Loading action, hold bolt in rear-

most position, check ejection of cases and, if necessary, remove anyjammed cases or cartridges.

– Turn gas valve on position II whenweapon is heavily fouled or iced up.

– Insert fresh magazine and load.– Set safety lever to desired firing

mode, continue firing.

If the weapon still will not fire:

– Put weapon on safe.– Unload per section 3.3.– Clean weapon in accordance with

4.1.– Take up firing position.– Load.– Set safety lever to desired firing

mode, continue firing.

If the weapon cannot be unloaded orthe fault rectified by the rifleman in accordance with the operating instruc-tions, a trained expert must be consult-ed. The following points must be bornein mind:

– If the weapon cannot be unloadedimmediately and there is any dangerof self-ignition due to a hot barrel(140° C), wait at least 15 minutes.

– The weapon must remain in positionas long as it is loaded.

– Spectators and other unnecessarypersons must be sent away so thatthe problem can be tackled carefullywithout disturbance.

– As long as the weapon is loaded, on-ly trained experts should be allowedto manipulate the weapon.

Malfunctions can largely be avoidedby:

– Cleaning the weapon according toitem 4.1. after each period of firing,at the latest just after setting thegas valve to position II.

– Carrying out cleaning in accordancewith the regulations.

– Loading the magazine correctly.

38

Maintenance

4. Maintenance

4.1. Cleaning

The SG 550/551 SP must be cleaned after each period of shooting. The fol-lowing sequence must be adhered to:

1. Unload the weapon per Section 3.3.2. Field strip the weapon (see Section

3.13.)3. Clean the barrel and cartridge cham-

ber from the rear.4. Clean the other parts of the weap-

on.5. Lubricate the barrel and chamber

with gun oil or grease.6. Smear the other parts of the weap-

on lightly with gun oil or grease.7. Reassemble the weapon in accord-

ance with item 3.14.8. Carry out a function check in accord-

ance with item 3.15.

39

Function

5. Function

5.1. Weapon function

5.1.1. Readiness to fire

At the moment of readiness to fire thebolt is closed and locked.

– the recoil spring (2) holds the boltcarrier (4) in the front final position,via the gas piston (1 ).

– the bolt head (5) is rotated by thecontrol cam (3) of the bolt carrier (4)in such a way that its locking lugs (8)engage in the corresponding re-cesses of the locking piece (9).

– in this position the hammer (7) iscocked.

Weapon loaded

9 8

1 2 3 4 5 6 7

40

Function

5.1.2. Discharging the shot

By pressing the trigger (11) the ham-mer (7) is released. The hammer is un-der pressure of the hammer spring (12)and strikes the firing pin (10) which, inturn, impacts against the cartridge primer of the cartridge (C) thus dis-charging the shot.

C 10 7 12

11Discharging the shot

41

Function

5.1.3. Unlocking and recoil of bolt

The gas pressure, generated by theburning powder, drives the bullet upthe barrel (13). As soon as the projectilepasses the gas port (15), propellant gasflows through the adjustable gas valve(14). The gas pressure acts on the gaspiston (1) which pushes the bolt carrier(4) to the rear.

Bolt carrier recoil begins

14 1 4

15 13

42

Function

During the rearward motion of thebolt carrier (4) the bolt head (5) is ro-tated by the control cam (3) so that thelocking lugs (8) are disengaged. Thebolt is now unlocked.

Unlocking begins

3 5 4

8

43

Function

The bolt assembly moves back alongthe rails in the receiver (16) as far asthe stop (17) whereby:– the recoil spring (2) is compressed;– the hammer (7) is cocked;– the extractor (18) extracts the case

from the chamber;– the ejector (19) ejects the case

through the port in the receiver (16).

2 16 7 17

19 18

Case ejection

44

Function

5.1.4. Bolt advance

The force of the compressed recoilspring (2) thrusts the bolt forward. Thebolt head (5) feeds the next roundfrom the magazine (20) into the cham-ber.

2 5

20

Bolt advance

45

Function

In the final stage of the advance, thebolt head (5) locks up. The weapon isready to be fired.

5 6

Locking

46

Anhang

300 Handguard311 Upper handguard321 Lower handguard330 Bipod complete**331 Leg, left**332 Leg, right**333 Bipod carrier**334 Stud**335 Circlip**336 Click stud**337 Bipod spring**

400 Bolt411 Bolt head412 Firing pin413 Firing pin stud414 Firing pin spring415 Extractor416 Extractor spring417 Pin421 Bolt carrier422 Bolt handle catch423 Axle of bolt handle catch424 Spring of bolt handle catch425 Bolt handle

200 Barrel/gas system211 Barrel*212 Front sight mount*213 Roll pin223 Stop pin224 Compression spring225 Spring pin231 Front sight232 Night front sight233 Positioning bolt234 Night front sight spring235 Spring pin236 Front sight screw*237 Front sight disc*238 Spring pin241 Gas valve251 Gas tube261 Gas piston262 Recoil spring263 Spring pin264 Spring pin265 Spacer268 Support washer

6 .Appendix

6.1. List of parts

100 Receiver111 Receiver casing141 Bolt cover142 Rivet151 Rear sight drum152 Drum spring153 Drum stud154 Luminous ampule*155 Insert156 Rubber disc161 Pivot162 Drum axle163 Spring washer164 Safety washer165 Leaf spring171 Windage correction srew172 Click stud173 Rear sight spring174 Limitation ring175 Spring pin181 Elevation correction screw

47

Anhang

500 Trigger assembly501 Trigger casing521 Magazine catch522 Magazine catch spring523 Magazine catch pin524 Bush541 Pistol grip542 Floorplate543 Allen screw544 Stop nut545 Nameplate551 Pressure point screw552 Stop nut553 Pressure point spring554 Trigger guard555 Trigger guard bearing561 Hammer562 Hammer axle563 Main spring564 Bolt catch565 Bolt catch spring566 Spring bolt

571 Safety lever572 Safety shaft573 Locking spring576 Spring pin581 Trigger582 Trigger spring583 Trigger rod584 Pivot, trigger585 Trigger bush586 Trigger rod spring591 Trigger casing stud592 Spring-pressure pin593 Spring for trigger casing stud594 Spring pin595 Pin596 Cup spring

600 Butt611 Buttstock612 Butt catch613 Butt catch spring614 Clip615 Spring pin616 Butt plate

700 Magazine711 Magazine casing712 Magazine floorplate713 Floorplate catch714 Feeder715 Magazine spring

* Cannot be ordered as individual parts

** Not on SG 551 SP

48

Anhang

6.2. Exploded drawing

Information to be supplied when or-dering spare parts:– Type of weapon– Serial number– Caliber– Item number– Parts designation

Subject to change without notice.