Heckler And Koch HK SL8-1 Operators Manual

							21 Forward assist
If the exterior of the rifle is very dirty (sand, mud etc.) the cocking lever
can also be used as a forward assist.
To use the cocking lever as a forward assist
1 •  Swivel out the cocking lever and push it inward against the bolt
head carrier (the cocking lever remains in its swiveled position).
2 •  Push the bolt head carrier with the cocking lever forward until it
fully locks closed.
3 •  Pull the cocking lever outward and let it swivel to its initial
position (parallel with the bolt head carrier).
Figure 23  Cocking lever shown in 
its “forward assist” position
Low-noise loading using the forward assist
1 •  After the magazine has been inserted, swivel out the cocking
lever and push it inward against the bolt head carrier until it
engages (see Figure 23).
2 •  Pull the cocking lever slightly to the rear and guide it forward.
3 •  Push the cocking lever forward until the bolt locks.
4 •  Pull the cocking lever outward and let it swivel to its initial
position (parallel with the bolt head carrier).
The rifle is now loaded and set at “Safe.”
WARNING: Never fire the SL8-1 with cocking handle locked in the90° forward assist position or injury may occur.
HANDLING AND OPERATION
20HANDLING AND OPERATIONReloading the Rifle
Method 2: The magazine in the weapon is empty.
The bolt has been held in its rear position by the bolt 
catch.
1 •  Set the safety/fire selector lever at “Safe.”
2 •  Push the magazine catch forward with the thumb and remove
the empty magazine (see Figure 22 below).
Figure 22  Release magazine (push forward)
3 •  Insert a loaded magazine into the magazine well until the
magazine clearly engages. Tug on the magazine to ensure it is
securely engaged.
4 •  Swivel the cocking lever out, pull it all the way to the rear and
release (see Figure 20).
The weapon is now loaded and set on “Safe.”   
						

							22OPERATION OF PARTSBolt Locked
The barrel is tightly screwed to the barrel extension by means of a nut.
The bolt head carrier houses the bolt head which can move along its
longitudinal axis inside the bolt head carrier. Additional to its longitudinal
movement the bolt head can also rotate around its longitudinal axis.
In the locked condition the bolt head is in the foremost position. The bolt
head in the bolt head carrier is turned in such a way that the locking
recesses of the bolt head engage the corresponding locking lugs of the
barrel extension.
The SL8-1 is now loaded and safety selector lever set to fire.
Pulling the trigger releases the hammer which hits the firing pin and
ignites the cartridge.
The propellant gases accelerate the bullet. As soon as the bullet has
passed the gas vent hole, a portion of the gases enter the gas block
and the gas cylinder.
These gases push the bolt head carrier via the gas piston and the push
rod to the rear. The camming slot in the bolt head carrier causes the
cam pin to pivot downward, which in turn rotates the bolt head and
unlocks it.
Figure 24 Bolt in locked position
1. Gas piston 6. Firing pin
2. Push rod 7. Camming slot
3. Bolt head 8. Barrel extension
4. Bolt head carrier 9. Barrel
5. Cam pin 10. Gas Block
23 Bolt Unlocked
The locking lugs disengage. The bolt head disengages (unlocks) from
the barrel extension. Bolt head carrier and bolt head move to the rear.
The extractor in the bolt head extracts the cartridge case by its rim from
the chamber. When the bolt assembly passes the ejection port, the
spring-loaded ejector ejects the cartridge case through the open
ejection port forward and to the right.
The rearward movement of the bolt assembly compresses the recoil
spring and cocks the hammer.
If the magazine is empty, the follower lifts the bolt catch upwards which
holds the bolt rearward. If a round is present in the magazine, the bolt
assembly, driven by the recoil spring moves forward and pushes the
uppermost cartridge out of the magazine into the chamber.
The bolt head contacts and stops at the rear face of the barrel and the
bolt head carrier continues its forward movement which rotates the bolt
head via the cam pin and the camming slot into the locked position.
The firing pin tip can only protrude through the bolt face and hit the
primer when the bolt is fully locked. The weapon is now ready to fire
again.
Figure 25  Bolt in the unlocked position
1. Gas piston 6. Firing pin
2. Push rod 7. Camming slot
3. Bolt head 8. Barrel extension
4. Bolt head carrier 9. Barrel
5. Cam pin 10. Gas block
OPERATION OF PARTS   
						

							25 Stripping into assembly groups
1 •  Use the 5 mm Allen wrench of the HK tool and remove the hex
headed Allen screws located on the left and right sides of at the
rear end of the receiver
2 •  Remove the locking pin above the front end of the trigger
guard.
3 •  Pull buttstock with trigger back out of the receiver.
4 •  Pull the cocking lever to the rear and remove the bolt.
5 •  Pull out the locking pin at the handguard and remove the
handguard to the front.
6 •  Push the magazine catch, swivel the magazine well downward
and detach.
Figure 26  Stripping SL8-1 into assembly groups
DISASSEMBLY OF THE SL8-1
24DISASSEMBLY OF THE SL8-1Clear the rifle! Before handling the firearm, “clear it!” Do so by:
1 •Make sure fingers are outside of the trigger guard and the
firearm is pointed in a safe direction at all times!
2 •ON SAFE – Rotate the safety/selector lever to the “Safe”
position (the white “S”adjacent to the safety/selector lever)
3 •REMOVE MAGAZINE – Depress the magazine paddle release
lever and remove the magazine from the magazine well.
4 •COCKING LEVER – Rotate the ejection port towards the
ground and fold out and pull the cocking lever rearward one or
more times to ensure the chamber is empty. Watch for a live
round or empty case to be ejected.
5 •BOLT CATCH – While holding the cocking lever fully rearward
use the trigger finger to press upwards on the bolt catch button
located in the front top corner of the trigger guard to lock the
bolt rearward.
6 •INSPECT CHAMBER – Inspect chamber for the presence of a
live round or empty case.
Visually – View chamber through open ejection port.
Physically –  Insert index finger through magazine well or
ejection port and feel for the presence of a round or cartridge
case in the chamber.
7 •Remove any live rounds or empty cases from the chamber or
from within the firearm or magazine before handling the firearm
further.
The HK SL8-1 is now considered “Clear.”Once clear, let the bolt move
forwards.NOTE: The SL8-1 is easily disassembled and reassembled with the
HK Tool. Do not use force in any of the disassembly procedures.
Disassembly beyond the procedures outlined in this manual is not
recommended and may void the HK Warranty. Disassembly beyond
the operators level described here may be carried out by qualifiedmaintenance personnel only. Contact HK for more information.  
						

							27 Disassembly of the bolt assembly
1 •  Push the firing pin retaining pin to the left (e.g. with
gas piston) and detach.
2 •  Remove the firing pin to the rear.
3 •  Take out the cam pin to the left.
4 •  Detach the bolt head to the front.
Figure 29  Bolt head disassembled
DISASSEMBLY OF THE SL8-1
26DISASSEMBLY OF THE SL8-1Disassembly of the push rod and the gas pistonCAUTION: The push rod is under considerable spring tension. Use
caution when installing and removing it. To avoid injury to yourself
and others, never point the compressed push rod in an unsafedirection in the event it is inadvertently released under pressure.
1 •  Push the push rod to the rear against spring pressure and
remove it from the gas piston.
2 •  Swivel the push rod to the side and remove it to the front.
3 •  Remove the gas piston to the rear.
Figure 27  Removing push rod
Figure 28  Removing the gas piston    
						

							29 Figure 31 Installing the push rod
Assembly of the SL8-1
1 •  Slide the handguard from the front over the barrel and the
receiver. Align notches onto studs.
2 •  Fasten the handguard with the locking pin.
3 •   Place the front of the magazine well onto the bearing studs,
swivel the rear of the magazine well upward all the way until it
engages the magazine catch.
4 •  Insert the bolt assembly from the rear into the receiver together
with the recoil spring.
5 •  Push buttstock assembly with trigger mechanism (hammer is
back, in the cocked position) from the rear into the receiver and
insert the locking pin above the trigger guard.
6 •  Fasten the buttstock to the receiver by the means of the allen
screws with the HK Tool (do not use excess force to tighten
them down).
7 •  Set the SL8-1 safety/selector on “Safe!”
8 •  Insert the magazine.
ASSEMBLY OF THE SL8-1
28ASSEMBLY OF THE SL8-1Assembly of the bolt
1 •  Slide the bolt head with the extractor on the right, as viewed
from the rear, into the bolt head carrier.
2 •  Insert the cam pin from the left into the bolt head carrier and
the bolt head; mind that the flat surfaces on the cam pin and
the hole for the firing pin are parallel to the bore.
3 •  Introduce the firing pin from the rear into the bolt head carrier
and the bolt head.
4 •  Insert the firing pin retaining pin from the left side into the bolt
head carrier to secure the firing pin and cam pin in place.
5 •  Determine that all parts are assembled in proper sequence and
complete and that the bolt head and cam pin moves freely
within the bolt head carrier.
Assembly of the gas system
1 •  Insert the gas piston into the gas block.
2 •  Introduce the push rod into the front part of the receiver, push it
against the spring pressure into the receiver and let it slide into
the gas piston.CAUTION: The push rod is under considerable spring tension. Use
caution when installing and removing it. To avoid injury to yourself
and others, never point the compressed push rod in an unsafedirection in the event it is inadvertently released under pressure.
Figure 30  Installing the gas piston   
						

							31 Buttstock adjustments
Cheekpiece and buttplate can be adjusted by means of removable
spacers to the user’s preference.
Adjustment of buttstock length
1 •  Use the 5mm allen wrench of the HK Tool to remove the hex
head screw on the left and right side of the rear of the buttstock
assembly.
2 •  Pull buttplate with spacer back out of the buttstock.
Figure 35 Remove buttplate with spacer
3 • To adjust the buttstock length to your requirement you can use
up to five spacers. Each spacer is 10 mm (approximately 1/2
inch wide). Maximum adjustment is 2 inches.
4 •  Push back buttplate with the required number of spacers into
the buttstock and fasten the two hex head screws with the HK
Allen wrench.
NOTE: The buttstock can be set at any length without the use of
optional spacers by using the two hex head screws to secure thebuttplate in position.
ADJUSTMENT OF THE STOCK & CHEEKPIECE
30DISASSEMBLY & ASSEMBLY OF THE MAGAZINEDisassembly of the magazine
1 •  Press the bottom of the right sidewall of the magazine inward
until the front catch is disengaged.
2 •  Push the magazine floor plate to the rear.
3 •  Press the bottom of the right sidewall inward until the rear catch
is disengaged.
4 •  Remove the floor plate to the rear.WARNING: The magazine spring is under pressure! Remove the
magazine spring and the follower from the bottom of the magazinewhile holding the magazine with the bottom pointed downward.
Figure 32                                      Figure 33              
Press magazine sidewalls                Remove floor plate   
Figure 34 Magazine disassembled
Assembly of the magazine
1 •  Insert the follower and the magazine spring from the bottom
into the magazine housing.
2 •  Slide the magazine floor plate from the rear onto the magazine
housing.
3 •  Push the magazine floor plate all the way over the two catches
onto the magazine housing.     
						

							33 Sight Adjustments
If the point of impact of several shots does not coincide with where you
aimed, a sight adjustment is necessary. The SL8-1 is zeroed at 100
meters point of aim point of impact using the 100 meter rear sight
aperture. For zeroing, select the 100 meter rear sight aperture.
Elevation Adjustment
•  If shots are high, elevation adjustment screw is turned clockwise with
the 2.5 mm Allen wrench of the HK Tool.
•  If shots are low, turn the screw counterclockwise.
•  A full turn of the adjustment screw will move the point of impact 11
cm or  4-1/2 inches up or down at a distance of 100 meters.
Figure 37  Elevation Adjustment
Windage Adjustment
•  If shots are right of the point of aim, use the 2 mm Allen wrench and
turn the windage adjustment screw clockwise.
•  If shots are to the left of the point of aim, turn the windage adjustment
screw counterclockwise.
•  One click of the side adjustment screw moves the point of impact 3.3
centimeters (or 1-1/4 inches) left or right.
Figure 38  Windage Adjustment
ADJUSTMENT OF THE SIGHTS
32ADJUSTMENT OF THE STOCK & CHEEKPIECEAdjustment of the cheekpiece
1 •  Use the Phillips screwdriver of the HK Tool to remove the two
Phillips screws from the cheekpiece.
2 •  You can use the cheekpiece alone or with up to two spacers.
3 •  Tighten the cheekpiece with or without spacers to the buttstock
by using the Phillips screwdriver.
Figure 36  Adjustment of cheekpiece     
						

							35 Optical sight with 3x magnification
Instead of the standard iron sights, an optional optical sight with 3x
magnification can be used on the SL8-1.
The sight comes with 2 Phillips screws, 2 spacers and 2 threaded
washers, to be mounted to the rail after removing front and rear sight.
Figure 40  Optical Sight
Optical Sight Reticle
The reticle of the optical sight is provided with range marks from 200 to
800 meters in increments of 200 meters.
The outer lateral surfaces of the circular reticle simultaneously serve as
lead marks when aimed at laterally moving targets, moving at
approximately 15 km/h (9m/h) speed at a range of 200 meters.
The interior diameter of the circular reticle corresponds to a target with
a height of 1.75 meters (or 5.5 feet) at a 400 meter range.
The range marks at the bottom left which help to find and set the range
at 200, 400 and 800 meters are also based on a target sized about 1.75
meters (5.5 feet).
In the same manner, the heights of the crossmarks at 600 m and 800 m
correspond to a target of approximately 1.75 m (5.5 feet) height at the
respective range.
OPTICAL SIGHTS
34ADJUSTMENT OF THE SIGHTS
Figure 39  Proper sight alignment 
NOTE: When engaging targets that are 300 meters away, flip the 300
meter rear sight aperture into position to account for the drop in thetrajectory of the projectile.  
						

							37 Figure 42Optical sight elevation adjustment on the SL8-1 
Windage Adjustment
•  If the weapon’s point of impact is too far to the right, turn the windage
adjusting screw counter clockwise in the direction of the “L.”
•  If the weapon’s point of impact is too far to the left, turn the windage
adjusting screw clockwise in the direction of the “H.”
NOTE: One graduation changes the point of impact by approx.2.3 centimeters (1.0 inch) at a range of 100 meters
Figure 43  Optical sight windage adjustment on the SL8-1 
OPTICAL SIGHTS
36OPTICAL SIGHTS
Figure 41  Optical reticle
1 Point of aim at 100 and 200 meters.
2 Lead mark for firing at targets moving from left to right at a
speed of approx. 15 km/h (9 mph) at a range of 200 meters.
3 Horizontal line to determine whether rifle is canted.
4 Circular reticle (interior diameter = 1.75 meters/5.5 feet size
target at 400 meter target range) and aiming point approx. 400
meter range.
5 Point of aim for firing at 600 meter range.
6 Point of aim for firing at 800 meter range.
7 1.75 meters/5.5 feet size target at ranges X.
Adjustment of the optical sight
If a sight adjustment becomes necessary, this may be done by vertically
or horizontally adjusting the optical sight with the 2.5 mm Allen wrench
from the HK Tool.
Elevation Adjustment
•  If the weapon’s point of impact is too high, turn the top adjusting
screw counter-clockwise in the direction of the “T.”
•  If the weapon’s point of impact is too low, turn the top adjusting screw
clockwise in the direction of the “H.”
NOTE: One graduation changes the point of impact by approx.2.3 centimeters (1.0 inch) at a range of 100 meters   
						

							39 HK SL8-1 Combination Tool:
All the necessary tools to adjust and field strip the SL8-1 are part of the
HK combination tool.
Figure 44   HK Combination Tool
1. Allen wrench 2 mm (iron sight, windage adjustment)
2. Allen wrench 2.5 mm (iron sight, elevation adjustment,
Optical sight, adjustment)
3. Allen wrench, 3 mm 
4. Allen wrench, 4 mm
5. Allen wrench, 5 mm (Allen head screws buttstock/receiver
and buttplate adjustment)                                 
6. Phillips screwdriver (cheekpiece adjustment)
7. Allen wrench, 6 mm
8. Screw driver, 5 mm
NOTE: Failure to use these metric tools may cause damage to theSL8-1 screws.
MAINTENANCE AND SERVICE
38MAINTENANCE AND SERVICECleaning and Preservation
To clean and maintain the SL8-1 self-loading rifle you may use:
• The HK cleaning kit caliber .223/5.56 mm
• Off the shelf cleaning kits caliber .223/5.56 mm
• Cotton patches and soft tissue
• Chloride and acid-free cleaning and preservation fluidsNOTE: Do not use steel tools or brushes to clean your SL8-1 or
synthetic materials like nylon when the weapon is hot. Keep
cleaning solvents away from the painted surfaces of the SL8-1, to
include the safety/selector and the “safe” and “fire” symbols. Proper
cleaning and maintenance of your SL8-1 will extend the life of therifle.
Normal Cleaning
You should do this after every firing of the gun:
1 •  Remove magazine
2 •  Set the SL8-1 safety/selector lever to “safe”and ensure the
chamber is clear
3 •  Use nylon brush and soft tissue to clean the outside
4 •  Lock bolt to the rear and run a bronze bristle bore brush
soaked with solvent several times through the barrel; follow with
clean patches
5 •  Apply a light coat of oil to the barrel
6 •  Following cleaning, check function of all parts
7 •  Set the SL8-1 safety/selector lever on “safe”
Major Cleaning (To be conducted after firing 1,000 rounds or if
exposed to or submerged in water):
1 •  Clean chamber and barrel extension with chamber brush
caliber .223/5.56 mm
2 •  Take bolt group apart and clean its parts
3 •  Disassemble the gas system and clean the gas piston
4 •  Field strip magazine and clean it
5 •  Apply light coat of oil to all moving parts including the metal
rails in the receiver
6 •  Reassemble the SL8-1 and check function
7 •  Set the SL8-1 safety/selector lever on “safe”