SIG SAUER SG552 User Manual
The safety warnings in this booklet are important.
By understanding the dangers inherent in the use of any
firearm, and by taking the precautions described herein,
you can enjoy complete safety in the use of your Rifle.
Failure to heed any of these warnings may result in serious
injury to you or others, as well as severe damage to the
firearm or other property.
Dangerous Weapons
PISTOLS, REVOLVERS, SHOTGUNS and RIFLES are classified as FIREARMS or DANGEROUS WEAPONS and are
sold by us with the specific understanding that we are
not responsible in any manner whatsoever for their safe
handling or resale under local laws and regulations. SAN
Swiss Arms AG shall not be responsible in any manner
whatsoever for malfunctioning of the firearm, for physical
injury or for property damage resulting in whole or in
part from (1) criminal or negligent discharge, (2) improper
or careless handling, (3) unauthorized modifications, (4)
defective, improper, hand-Ioaded, or reloaded ammunition,
(5) corrosion, (6) neglect, or (7) other influences beyond
our direct and immediate control. This limitation applies
regardless of whether liability is asserted on the basis of
contract, negligence or strict liability (including any failure
to warn). Under no circumstance shall SAN Swiss Arms
AG be liable for incidental or consequential damages,
such as loss of use of property, commercial loss and loss
of earnings or profits.
12 commandments of firearms safety
1 ALWAYS treat every gun as if it were loaded.
2 ALWAYS be sure the barrel is clear of 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 factory- made ammu-
nition of the proper type and caliber for your gun.
5 ALWAYS wear ear protection and safety glasses when
shooting.
6 ALWAYS carry your gun so that you can control the
direction of the muzzle if you fall or stumble.
7 NEVER shoot at a flat surface or water.
8 DO NOT leave an unattended gun loaded. Guns and
ammunition should be stored separately, locked if
possible, beyond the reach of children and careless
adults.
9 NEVER allow your firearm to be used by anyone
who has not read and understood this instruction
and Safety manual.
10 DO NOT point any gun, loaded or unloaded, at any
undesired target.
11 NEVER fire your rifle near an animal unless it is trained
to accept the noise: an animal’s startled reaction could
injure it or cause an accident.
12 NEVER drink alcoholic beverages or take drugs before
or during shooting, as your vision and judgement could
be seriously impaired making your gun handling unsafe.
2
3
Safety warnings
Page
1. Safety warnings......................................................... 3
2. Weapon theory......................................................... 11
2.1. Weapon description................................................. 11
2.2. Technical specifications........................................... 20
2.3 Accessories............................................................... 21
3. Handling ................................................................... 22
3.1. Important instructions............................................. 22
3.2. Loading the weapon ................................................ 22
3.3. Unloading................................................................. 23
3.4. Changing the magazine .......................................... 23
3.5. Reloading.................................................................. 23
3.6. Filling and coupling of magazines......................... 24
3.7. Aiming, firing and adjusting with diopter sight.... 25
3.8. Aiming, firing and adjusting with flip up sight..... 28
3.9. Gas valve position................................................... 29
3.10. Folding the butt stock.............................................. 30
3.11. Firing with mittens or gloves.................................. 30
3.12. Rifle grenades .......................................................... 31
3.13. Use of accessories....................................................32
3.14. Field stripping .......................................................... 33
3.15. Assembly.................................................................. 37
3.16. Function check ......................................................... 40
3.17. Procedure in case of malfunction .......................... 41
4. Maintenance............................................................. 42
4.1. Types of maintenance............................................. 42
4.2. Cleaning and lubrication procedures ......................43
5. Function.................................................................... 45
5.1 General weapon function of SG 55X..................... 45
5.2. Trigger functions.......................................................48
6. Appendix .................................................................. 56
6.1. List of parts............................................................... 56
6.2. Exploded drawing.................................................... 59
Contents
•A shot sounds weak or abnormal. In such cases it is
possible that a bullet is lodged part way down the barrel. Firing a subsequent bullet into the obstructed barrel can wreck the firearm and cause serious injury to
the shooter or to bystanders.
5 Bullets can become lodged in the barrel:
• If the cartridge has been improperly loaded without
propellant powder, or if the powder fails to ignite,
(ignition of the cartridge primer alone will push the
bullet out of the cartridge case, but usually does not
generate sufficient energy to expel the bullet completely
from the barrel), or
• If the bullet is not properly seated tightly in the cartridge
case. When such a cartridge is extracted from the
chamber without being fired, the bullet may be left
behind in the bore at the point where the rifling begins.
Subsequent chambering of another cartridge may push
the first bullet further into the bore.
6 If there is any reason to suspect that a bullet is obstruc-
ting the barrel, immediately unload the firearm and
look through the bore. It is not sufficient to merely look
in the chamber. A bullet may be lodged some distance
down the barrel where it cannot easily be seen.
IF A BULLET IS IN THE BORE, DO NOT ATTEMPT TO
SHOOT IT OUT BY USING ANOTHER CARTRIDGE, OR BY
BLOWING IT OUT WITH A BLANK OR ONE FROM WHICH
THE BULLET HAS BEEN REMOVED: SUCH TECHNIQUES
CAN GENERATE EXCESSIVE PRESSURE, WRECK THE
FIREARM AND CAUSE SERIOUS PERSONAL INJURY.
If the bullet can be removed with a cleaning rod, clean
any unburned powder grains from the bore, chamber,
and mechanism before resuming shooting. If the bullet
cannot be dislodged by tapping it with a cleaning rod,
take the firearm to a gunsmith.
7 Dirt, corrosion, or other foreign matter on a cartridge
can impede complete chambering and may cause the
cartridge case to burst upon firing. The same is true of
cartridges which are damaged or deformed.
8 Do not oil cartridges, and be sure to wipe the chamber
clean of any oil or preservative before commencing to
shoot. Oil interferes with the friction between cartridge
case and chamberwall that is necessary for safe functioning, and subjects the firearm to stress similar to that
imposed by excessive pressure.
9 Use lubricants sparingly on the moving parts of your
firearm. Avoid excessive spraying of any aerosol gun
care product, especially where it may get on ammunition.
5
Safety warnings
Protect your eyes and ears
Always wear adequate safety glasses and ear plugs or
“earmuff” type protectors whenever you are shooting.
Always make certain that persons close to you are similarly
protected. Unprotected eyes may be injured by powder
gas, carbon residue, lubricant, metallic particles or similar
debris which may emanate occasionally from any firearm
in normal use. Without ear protection, repeated exposure
to shooting noise may lead to cumulative, permanent
hearing loss.
Ammunition
1 Use only high quality, original factory-manufactured
ammunition. Do not use cartridges that are dirty, wet,
corroded, bent, or damaged. Do not oil cartridges. Do
not spray aerosol-type lubricants, preservatives, or
cleaners directly onto cartridges or where excess spray
may flow into contact with cartridges. Lubricant or
other foreign matter on cartridges can cause potentially
dangerous ammunition malfunctions. Use only ammunition of the caliber for which your firearm is chambered. The proper caliber is permanently engraved on
your firearm; never attempt to use ammunition of any
other caliber.
2 The use of reloaded, “remanufactured”, hand-Ioaded,
or other non-standard ammunition voids all warranties.
Reloading is a science and improperly loaded ammunition can be extremely dangerous. Severe damage to
the firearm and serious injury to the shooter or to others
may result. Always use ammunition that complies with
the industry performance standards established by
the Sporting Arms and Ammunition Manufacturers’
Institute, Inc. of the United States (SAAMI) or ammunition manufactured to military specifications.
3 Firearms may be severely damaged and serious injury
to the shooter or to others may result from any condition
causing excessive pressure inside the chamber or barrel
during firing. Excessive pressure can be caused by
obstructions in the barrel, propellant powder overloads,
or by the use of incorrect cartridges or defectively
assembled cartridges. In addition, the use of a dirty,
corroded, or damaged cartridge can lead to a burst
cartridge case and consequent damage to the firearm
and personal injury from the sudden escape of highpressure propellant gas within the firearm’s mechanism.
4 Immediately stop shooting and check the barrel
for a possible obstruction whenever:
•You have difficulty in, or feel unusual resistance in,
chambering a cartridge, or
•A cartridge misfires (does not go off), or
• The mechanism fails to extract a fired cartridge case, or
•Unburned grains of propellant powder are discovered
spilled in the mechanism, or
Safety warnings
4
Firing
1 Keep the muzzle pointed in a safe direction and your
finger away from the trigger when cocking any firearm.
2 Never carry about or leave unattended any firearm
which is cocked and ready to fire! When cocked, it will
fire from slight pressure on the trigger. An accidental
discharge could easily result if you fall or drop the firearm, or if the firearm is struck or disturbed by someone
or something.
3 Never fire any firearm with your finger, hand, face, or
other part of your body over or adjacent to the ejection
port, or in any position where you may be struck by
reciprocating movement of the breech. Both the ejection
of empty cartridge cases and the movement of the breech
are part of the normal operating cycle of firearms, and
pose no safety hazard to the shooter if the firearm is
held in a normal grip and fired at arm’s length.
4 Never allow other persons to stand beside you where
they might be struck by an ejected cartridge case. The
case is hot, and may be ejected with sufficient force to
cause a burn or cut or injure an unprotected eye. Make
certain there is a clear, unobstructed path for safe ejection of the fired case. Remember, the case may bounce
off a hard object nearby and strike you or someone
else.
5 If, while shooting, your firearm develops a mechanical
malfunction or binding, or “spits” powder gas, or if
a cartridge primer is punctured or a cartridge case is
bulged or ruptured, or if the report on firing does not
sound quite right, STOP SHOOTING IMMEDIATELY! It
may be dangerous to continue. UNLOAD THE FIREARM
– do NOT try “one more shot”. Take the firearm and the
ammunition to a gunsmith for examination.
6 While shooting any firearm, an unfired cartridge or fired
cartridge case may occasionally become jammed between the bolt and the barrel. Clear the jam as follows,
WHILE KEEPING THE MUZZLE POINTED IN A SAFE
DIRECTION: Remove the magazine, then pull back the
bolt by way of the bolt handle and lock it to the rear by
pushing up the slide catch. The jammed cartridge or
case now can be removed by shaking it out or by pikking it out with the fingers.
Unloading
1 Always make sure the muzzle is pointed in a safe
direction!
2 Remember to clear the chamber after the magazine
has been removed.
3 Never assume that any gun is unloaded until you have
personally checked it, visually and physically!
7
Safety warnings
All lubricants and aerosol spray lubricants in particular
can penetrate cartridge primers and cause misfires.
Some highly penetrative lubricants can also migrate
inside cartridge cases and cause deterioration of the
propellant powder; on firing, the powder may not ignite. If only the primer ignites, there is danger that the
bullet may become lodged in the barrel.
NEVER completely trust any safety
1 Your firearm comes equipped with an effective, well-
designed safety device. HOWEVER, NEVER RELY COMPLETELY ON ANY SAFETY MECHANISM. It is NOT a
substitute for cautious gun handling. NO safety, however
positive or well-designed, should be totally trusted. Like
all mechanical devices, the safety is subject to breakage
or malfunction and can be adversely affected by wear,
abuse, dirt, corrosion, incorrect assembly, improper
adjustment or repair, or lack of maintenance. Moreover,
there is no such thing as a safety which is “child-proof”
or which can completely prevent accidental discharge
from improper usage, carelessness, or “horseplay”.
The best safety mechanism is your own good sense;
USE IT! Always handle your firearm as though you
expect the safety NOT to work!
2 While handling any firearm, do not allow it to point at
any part of your body or at another person. No harm
will result if you obey this rule, even if an accidental
discharge occurs.
3 Never carry this rifle with a cartridge in the chamber
and the hammer cocked.
4 Always keep your finger off the trigger and point the
muzzle in a safe direction when operating the gun
release.
Loading
1 Always make sure the muzzle is pointed in a safe
direction!
2 Never attempt to load or unload any firearm inside a
vehicle, building or other confined space (except a
properly constructed shooting range). Enclosed areas
frequently offer no completely safe direction to point
the firearm; if an accidental discharge occurs, there is
great risk of injury or property damage.
3 Before loading, always clean all grease and oil from the
bore and chamber, and check to be certain that no
obstruction is in the barrel. Any foreign matter in the
barrel could result in a bulged or burst barrel or other
damage to the firearm, and could cause serious injury
to the shooter or to others.
Safety warnings
6
A firearm is a precision instrument and some replacement
parts will require individual fitting to insure correct operation.
A wrong part, improper fitting or incorrect mechanical
adjustment may result in an unsafe condition or dangerous malfunction, damage to the firearm, or possible
serious injury to the shooter or to others. IF ANY PART IS
ORDERED WITHOUT RETURNING THE FIREARM TO SAN
SWISS ARMS AG, the customer bears full responsibility
for ensuring that the part supplied is correct for his
particular firearm and is properly installed and fitted by
a qualified gunsmith. SAN SWISS ARMS AG CANNOT
BE RESPONSIBLE FOR THE FUNCTIONING OF ANY FIREARM IN WHICH REPLACEMENT PARTS ARE INSTALLED
BY OTHERS.
SAN SWISS ARMS AG service policy
Before shipment your firearm was carefully inspected
and test fired in order to ensure that it conformed to our
specifications and standards. Should your firearm require
adjustment, repair or refinishing, we strongly recommend
that you return it to SAN Swiss Arms AG for factory service.
If there is any question regarding the performance
of your firearm, please write to SAN Swiss Arms AG.
Service Department fully describing all circumstances
and conditions involved. If our Service Department makes
the determination that your firearm requires factory service,
you will be so advised and will be given instructions for
the most expeditious handling of your shipment.
Our Service Department will give your firearm a complete
inspection, and evaluate the problem(s) specified in your
letter.lf the work required is not covered under the terms
of our “Limited Warranty” (a copy is enclosed with your
firearm), you will receive an actual cost quotation, not an
estimate. Any repair work must be authorized by you,
and no work will be done without your express approval.
To return any firearm to us for adjustment, repair or
refinishing, please follow these suggestions to expedite
service:
1 Only federally licensed dealers may ship handguns via
the mail. Handguns mailed by individuals are confiscated
by the Post Office.
2 Federal law permits you to return your firearm to the
manufacturer for service via common carriers or, if your
firearm is a rifle or shotgun, by mail. However, state
and local firearms laws vary greatly; you should consult
your local prosecuting attorney regarding any restrictive
laws in your jurisdiction regarding your shipment or
receipt of firearms. With the above in mind, it is strongly
9
Safety warnings
4 After every shooting practice, make a final check to
be certain the firearm is unloaded before leaving the
range.
Transport and storage
When transporting your firearm to and from shooting
activities, keep it unloaded for your safety and for the
safety of others. When storing your firearm, keep it separated from ammunition, under lock and key if possible,
and out of the reach of children and other inexperienced
or unauthorized persons.
Maintenance
All firearms require periodic maintenance and inspection
which may reveal a need for adjustment or repair. Have
your firearm checked by a competent gunsmith annually
even if it seems to be working well, since breakage,
improper functioning or corrosion of some components
may not be apparent from external examination. If you
notice any mechanical malfunction, do NOT continue to
use the firearm. UNLOAD the firearm and take it to a
competent gunsmith immediately for a thorough examination. Similarly, if water, sand, or other foreign matter
enters the internal mechanism, immediately dismantle
the firearm for a complete and thorough cleaning. Failure
to keep your firearm clean and in proper working order
can lead to a potentially dangerous condition and an acci-
dent causing serious bodily injury or property damage
may result.
Care and cleaning
1 Your firearm is delivered factory packaged and preserved
with a light coating of protective grease and oils. Before
loading make certain that all packing grease and oil has
been cleaned from the bore and exposed mechanism.
2 Before you begin to disassemble your firearm for clea-
ning, always double-check to make sure it is unloaded!
3 After cleaning always check to be sure that no cleaning
patch or other obstruction remains in the bore or chamber!
Parts
Our Service Department maintains a full complement of
replacement parts. Even though most gunsmiths have
the knowledge, training and ability to make the necessary
repairs to your firearm, the skill and workmanship of any
particular gunsmith is totally beyond our control. Should
your firearm ever require service, we strongly recommend that you return it to SAN Swiss Arms AG. Follow
the instructions outlined below. Remember, unauthorized
adjustments of parts replacement can void your warranty.
Safety warnings
8
2. Weapon theory
2.1. Weapon description
2.1.1. General
The SG 552 is a gas operated weapon with rotary bolt
mechanism.
SG 552
1) standard version with diopter sight.
SG 552
2) standard version with picatinny rail
with flip up front and rear sight.
11
Weapon theory
recommended that any firearm sent to us for repair
should be sent through a federally licensed dealer.
3 All firearms must be shipped to us prepaid.
WE WILL NOT ACCEPT COLLECT SHIPMENTS.
4 Firearms returned for repair should be addressed to:
SAN Swiss Arms AG, Industrieplatz, 8212 Neuhausen
am Rheinfall, Switzerland.
5 Be sure to enclose a letter stating serial number, caliber
and barrel length of your firearm. Also state nature of
trouble experienced or work required. Merely stating
“defective” or “repair as necessary” is inadequate
information. Be specific and enclose copies of any
previous correspondence.
6 FIREARMS MUST BE SHIPPED UNLOADED. Double-
check the chamber of your firearm before shipping.
If firearms are sent to SAN Swiss Arms AG in a loaded
condition, we are required by law to notify the Federal
authorities.
7 DO NOT include telescopic sights, custom stocks,
slings, or other accessories with any firearm shipped
to us.
8 To expedite service, include a day time phone number
that a person familiar with the reason on return may be
contacted at.
Safety warnings
10
illu. 1) SG 552 with diopter sight
illu. 2) SG 552 with picatinny rail
SG 552 LB
3) long barrel version with diopter sight.
SG 552 LB
4) long barrel version with picatinny rail
with flip up front and rear sight.
The rifle SG 552 can be used:
• at distances of up to 300 m,
in semi automatic fire
in rapid semi automatic fire
in three-round bursts
in full auto operation
•at distances of up to 400 m,
when fitted with telescopic sights
• with the bayonet attached, as a club
and as a blank weapon (on SG 552 LB only).
The SG 552 can be fired with the stock in
the normal position or folded.
2.1.2. Barrel with receiver and gas system
The barrel is screwed into the receiver. The muzzle is
equipped with sc rewed on or integrated 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 or
integrated picatinny rail with flip up rear sight are also
mounted on top of t he re c ei v er.
Weapon theory
12
13
Weapon theory
illu. 3) SG 552 LB with diopter sight
illu. 4) SG 552 LB with picatinny rail
illu. 5) Barrel with receiver and gas system
1 Flash suppressor
2 Gas valve
3 Barrel
4 Front sight
5 Gas piston
6 Gas tube
7 Bolt carrier
8 Rear sight mount
9 Diopter drum
10 Recoil spring
11 Recoil spring guide
12 Receiver casing
13 Front sight mount
1324 56 7 8
1213
9 10 11
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
15
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
14
illu. 6) Bolt head illu. 7) Bolt carrier with gas piston from left illu. 9) Handguardillu. 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
123 5
4
1
2
765 4 23
2.1.6. Diopter Sights mechanism
The diopter sights mechanism comprise the rear 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 positions “1”, “2” and
“3”, corresponding to firing ranges 1OO m, 2OO m and
3OO m The positions marked in white correspond to
aiming point = point of impact.
Sighting position “1” is designed for immediate firing,
and two luminous dots are fitted laterally for aiming at
night.
The foresight with tunnel is fixed to its mount with the
foresight screw. A folding foresight is provided for use
at night with the night sights on the diopter drum.
Rearsight assembly (illu.12)
1 Receiver casing
2 Rear sight mount
3 Elevation correction screw
4 Rear sight drum
5 Night sight
6 Windage correction screw
Front sight (illu.13)
1 Front sight tunnel
2 Front sight
3 Night front sight
4 Front sight screw
17
Weapon theory
2.1.5. Trigger assembly and butt stock
The trigger assembly comprises all the parts required for
firing a shot. The safety lever on both sides can be set to
four positions:
Position “S“: The weapon is locked in the safe position.
Position “1“: The weapon will fire semi auto.
Position “3“: The weapon fires 3-round burst.
After each burst, the trigger must
be released and then pulled again.
Position “20“: The weapon fires in the full auto mode.
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 stock is made of high strength synthetic
material. In the firing position it is held by the butt locking
mechanism, and when folded it is held by spring pressure
on the handguard.
Trigger assembly and butt stock from right (illu. 10)
1 Butt stock 4 Magazine catch
2 Safety lever 5 Trigger
3 Trigger casing 6 Pistol grip
Trigger assembly and butt from stock from left (illu. 11)
1 Trigger casing 5 Butt stock catch
2 Bolt catch 6 Pistol grip
3 Safety lever 7 Trigger guard
4 Butt stock 8 Magazine catch
Weapon theory
16
illu. 11) Trigger assembly and butt from stock from left illu.12)
Rear sight assembly
illu. 13) Front sight
illu. 10) Trigger assembly and butt stock from right
1123 4 5 6
2
3
4
1
1 2 3
4
23
45
6
8 7 5
6
2.1.7. Magazine
The magazine is transparent and has a capacity of 5,10,20
and 30 rounds. On either side of the 20 and 30 rounds
casing there is a mechanism which allows several magazines to be connected if required.
Magazine, dismantled (illu. 16)
1 Feeder
2 Magazine spring
3 Magazine floorplate catch
4 Magazine floorplate
5 Magazine coupling lugs
6 Magazine casing
19
Weapon theory
2.1.6.2. Flip up sight mechanism
The flip up sight mechanism comprise the rear and
front flip up sight. The rear sight is made up of the:
• Rear sight holder
• Rear sight
• Flat head screw
The rear sight is marked with “100“, corresponding to
firing range 100 m.
The foresight is fixed to its mount with the foresight
screw. The folding foresights are mounted on the lower
part of the foresight.
Flip up rear sight (illu. 14)
1 Rear sight holder
2 Rear sight
3 Flat head screw
Flip up front sight (illu.15)
1 Front sight
2 Front sight holder
3 Front sight screw
Weapon theory
18
illu. 14) Flip up rear sight illu. 15) Flip up front sight
illu. 16) Magazine, dismantled
1 2 3
65 4
1
2
3
1
2
3
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