CONTRACT NUMBER N00164-94-C-0040
SW370-BD-OPI-010
Operator’s Manual
Mark 23 Pistol, Semi-automatic,
Caliber .45 ACP
®
© Heckler & Koch, Inc., October 1996
21480 Pacific Blvd.
Sterling, Virginia 20166-8903
United States of America
Telephone (703) 450-1900
1
WARNING
A firearm has the capability of taking your life or the life of someone else! Be extremely careful with your
firearm. An accident can occur at anytime and is almost always the result of not following basic safety rules.
CHAPTER 1
SECTION I
SECTION II
CHAPTER 2
SECTION I
SECTION II
SECTION III
SECTION IV
TABLE OF CONTENTS
PAGE
INTRODUCTION ..................................................................................................................................................... 4
GENERAL INFORMATION ........................................................................................................................................ 4
PISTOL DESCRIPTION ............................................................................................................................................ 6
1.2 Nomenclature ................................................................................................................................ 6
1.3 Principle of Operation .................................................................................................................. 7
1.4 Major Assembly Groups ............................................................................................................... 7
1.5 Technical Specifications ............................................................................................................... 9
OPERATING INSTRUCTIONS ............................................................................................................................. 10
SERVICE UPON RECEIPT OF MATERIAL ........................................................................................................... 10
2.1 Initial Inspection ......................................................................................................................... 10
GENERAL DESCRIPTION .................................................................................................................................... 10
2.2 Description .................................................................................................................................. 10
2.3 Operation and Characteristics ................................................................................................... 11
2.4 Cycle of Operation ..................................................................................................................... 13
2.5 Safety Features .......................................................................................................................... 17
OPERATION UNDER NORMAL CONDITIONS .................................................................................................. 18
2.6 Clearing Procedures .................................................................................................................. 18
2.7 Loading and Unloading the Magazine ....................................................................................... 19
2.8 Loading Procedure ..................................................................................................................... 20
2.9 Readying the Pistol for Firing .................................................................................................... 21
2.10 Firing the Pistol ........................................................................................................................ 22
OPERATION UNDER UNUSUAL CONDITIONS ................................................................................................ 23
2.11 Extreme Cold ............................................................................................................................ 23
2.12 Hot, Wet Climates .................................................................................................................... 23
2.13 Hot, Dry Climates ..................................................................................................................... 24
2.14 Heavy Rain and Water Operations - All Climates ................................................................... 24
2
SECTION V MALFUNCTIONS AND STOPPAGES .................................................................................................................. 25
2.15 Remedial Action ........................................................................................................................ 25
CHAPTER 3 MAINTENANCE INSTRUCTIONS ....................................................................................................................... 27
SECTION I TOOLS & EQUIPMENT .......................................................................................................................................... 27
3.1 Operator Tools and Equipment Required .................................................................................. 27
SECTION II PMS CHECKS & MAINTENANCE PROCEDURES .............................................................................................. 27
3.2 General ....................................................................................................................................... 27
3.3 Disassembly (Field stripping) ..................................................................................................... 28
3.4 Reassembly (From field strip) .................................................................................................... 30
3.5 Safety/Function Check ............................................................................................................... 33
3.6 Function Firing ............................................................................................................................ 36
3.7 Cleaning ..................................................................................................................................... 36
3.8 Inspection ................................................................................................................................... 37
3.9 Lubrication .................................................................................................................................. 38
SECTION III ADJUSTMENT OF SIGHTS ................................................................................................................................. 40
SECTION IV TROUBLESHOOTING PROCEDURES ............................................................................................................... 43
3.10 Operator Troubleshooting Procedures .................................................................................... 43
3.11 Parts Listing and Exploded Diagram ....................................................................................... 46
CHAPTER 4 AMMUNITION ....................................................................................................................................................... 48
FIREARM SERVICE RECORD ................................................................................................................... INSIDE BACK COVER
3
CHAPTER 1
INTRODUCTION
SECTION I - GENERAL INFORMATION
The HK Mark 23 .45 ACP pistol give shooters match
grade accuracy equal to that of the finest custom made
handguns — yet it exceeds the most stringent operational
requirements ever demanded of a combat handgun.
The Mark 23 provides this accuracy without the need for
hand-fitted parts common in custom-built match pistols
costing thousands of dollars more. Repair of the Mark 23
is reduced to a simple parts exchange.
The HK Mark 23, is a commercial model of the U.S.
Government issue MK 23, MOD 0 pistol and is available
in limited numbers. Designated the “Mark 23”, it is almost
identical to the MK 23, MOD 0 pistol used by the Special
Operations Command, right down to its threaded barrel.
The main differences are slide Markings (Mark 23 as
opposed to MK 23) and a barrel manufactured to SAMMI
headspace specifications.
One of the most thoroughly tested handguns in history,
the MK23/Mark 23 project originated in 1991 when HK
was awarded a development contract for the Special
4
Operations Forces Offensive Handgun Weapon System,
consisting of a caliber .45 pistol, detachable sound and
flash suppressor, and laser aiming module (LAM).
During testing, MK 23 pistols met the most stringent
operational and accuracy requirements ever demanded of
a combat handgun. MK 23 pistols achieved match grade
accuracy of less than a 2.5 inch maximum extreme
spread in 5-round shot groups at 25 meters with service
ammunition. Endurance testing demonstrated a service
life of over 30,000 rounds of +P ammunition with no parts
breakage, with an additional 30,000 rounds certified on
the slide and frame.
To meet the reliability requirement, the pistol had to
demonstrate a minimum of 2,000 mean rounds between
stoppages (MRBS) with both M1911 ball and +P
ammunition. The minimum MRBS achieved in testing was
6,027 and the maximum was 15,122!
During over 450 accuracy test firings from a precision
firing fixture, MK 23 pistols far exceeded the government
requirement, averaging 1.44 inches, with 65 groups of
less than one inch. There were four groups of .5 inches,
with 5 rounds going through the same hole! This included
firing with and without the sound/flash suppressor
attached.
Three pistols were tested for accuracy after firing over
30,000 rounds, the specified service life of the pistol, and
still met the new pistol accuracy requirement. An
innovative design feature, a high temperature rubber Oring on the barrel that seals the barrel in the slide until
unlocking, led to this remarkable achievement. The O-ring
lasts beyond 20,000 rounds and can be replaced by the
operator without tools in seconds.
To meet operational environmental requirements, the
pistol was function tested at +140 and -250 F, immersed in
salt water, exposed to surf, salt-fog, sand-dust, mud,
icing, unlubricated, and a variety of other fouled
environments. A special maritime surface coating protects
the pistol from corrosion, in all of these operational
environments.
The barrel is threaded to accept accessories such as a
flash and sound suppressor. The unique HK polygonal
bore profile increases muzzle velocity and service life,
reduces bore fouling and eases cleaning.
The frame mounted MK 23 decocking lever is separate
from the ambidextrous safety lever. It allows the hammer
to be lowered quietly and safely from the single action
position. When the hammer is down, the ambidextrous
frame mounted safety lever is locked in the fire position
so that the pistol is always ready for double action
5
operation. When the hammer is “cocked and locked” in
single action mode with the safety lever on “safe”, the
decocker is blocked so that the pistol is always ready for
single action operation. Even with the safety lever
engaged, the slide can still be manipulated to load and
clear the pistol.
The extended slide release lever and the ambidextrous
magazine release are easily operated without adjustment
of the firing grip using the firing hand thumb or index
finger.
Other notable features include accessory mounting
grooves on the frame, a mechanical recoil reduction
system that reduces recoil forces to the shooter and
components of the pistol by as much as 30%, a polymer
frame, a one-piece machined steel slide, and a law
enforcement/military magazine capacity of twelve rounds.
The weapon is aimed using either iron sights or an
optional laser aiming component. The iron sights provide
a 3-dot sight picture with white or optional self-luminous
tritium dots.
The MK 23 became the first caliber .45 ACP pistol to
enter U.S. military service since the venerable
Government Model 1911A1. On May 1, 1996, the first MK
23 pistols were delivered to the U.S. Special Operations
Command for operational deployment.
magazine
release
slide release
recess for slide
release/stop
SECTION II - PISTOL DESCRIPTION
slide
1.2 Nomenclature
threaded barrel
accessory
mounting
groove
threaded insert
for accessory locking
flared
trigger guard
magazine
Figure 1 Left View
1.3 Principle of Operation
hammer
left safety
lever
decocking
lever
frame
A. The Mark 23 uses a modified linkless Browningstyle short recoil system to lock and unlock the
breech.
6
rear sight
right
safety lever
lanyard loop
extractor
trigger
barrel locking
block
magazine
release
ejection
port
slide release
axle recess
Figure 2 Right View
front sight
accessory
mounting
groove
B. Upon firing, the pressure developed by the
propellent gas forces the slide and barrel
assembly to the rear. After approximately 3 mm,
the locking block will stop the rearward
movement of the barrel as the barrel is pivoted
downward due to the engagement of the angled
surfaces of the locking block with those located
in the recoil spring guide rod. The locking block
will disengage from the slide and the slide will
continue rearward.
The extractor located in the slide will then
extract the fired cartridge case, the ejector
located in the frame on the left side of the
magazine well will eject the fired case as the
slide continues rearward and cocks the
hammer, and compresses the recoil spring.
The slide moves forward feeding the next
cartridge from the magazine into the chamber
and locking to the barrel breech.
C. The slide locks open after the last round has
been fired and ejected.
WARNING
Do not rely on the slide lock to determine if
the magazine is empty. Always check visually
and physically ensure the pistol is not loaded.
1.4 Major Assembly Groups (See Figure 3)
A. Slide - houses the firing pin, firing pin block and
7
extractor; cocks hammer during recoil.
B. Captured Recoil/Buffer Spring Assembly
(with guide rod) - absorbs recoil and returns
the slide and barrel to their forward positions;
reduces impact of slide on receiver during
recoil. The recoil spring is “captured” by a C-clip
on the end of the guide rod.
C. Threaded Barrel (with locking block) contains cartridge and propellent gases during
firing. The locking block initiates locking and
unlocking of the breech during movement of
slide. The O-ring holds the barrel tight in the
slide until unlocking.
D. Frame - serves as support to all major
components; controls functioning of pistol. The
slide release locks the slide with barrel and
recoil/buffer spring assembly to the metal
locking insert cast into the synthetic frame. A
lanyard loop is in the bottom of the grip for
attaching a lanyard. The trigger guard is flared
on both sides to preclude accidental actuation
of the magazine release during holstering.
buffer spring
O-ring
A. Slide
E. Magazine - holds the cartridges in position for
feeding and chambering.
C. Threaded
Barrel
threads
guide rod
C-clip
recoil spring
accessory
mounting groove
threaded insert for
accessory locking
flared trigger guard
F. Slide Release
E. Magazine
F. Slide Release - holds slide to rear when
engaged; releases slide when lever is
depressed.
barrel locking block
lanyard loop insert
D. Frame
decocker
safety
B. Captured Recoil/Buffer
Spring Assembly
magazine
release
Figure 3 Major Assembly Groups
8
1.5 Technical Specifications:
polygonal bore right hand twist
.45 ACP (Automatic Colt Pistol)
short recoil, semi-automatic
Browning system (modified), linkless
5.87 in.
(149 mm)
7.76 in.
(197 mm)
9.65 in.
(245 mm)
.24 lbs.
(.110 kg)
.81 lbs.
(.366 kg)
.72 lbs.
(.327 kg)
2.66 lbs.
(1.21 kg)
3.22 lbs.
(1.46 kg)
3.13 lbs.
(1.42 kg)
4.85 lbs.
(2.20 kg)
12.13 lbs.
(5.50 kg)
5.90 in.
(150 mm)
1.53 in.
(38.8 mm)
886 fps
(270 m/s)
1142 fps
(348 m/s)
54.7 yds
(50 m)
1,467 yds
(1,341 m)
staggered, 12 round capacity (10 round civilian)
Caliber
System of Operation
Locking System
Length
Barrel
Sight radius
Pistol
Weight
Magazine (empty) 12 or 10 rd. capacity
Magazine (w/12 rds M1911 Ball)
Magazine (w/10 rds M1911 Ball)
Pistol (w/ empty 12 or 10 rd magazine)
Pistol (w/ 12 rds M1911 Ball)
Pistol (w/ 10 rds M1911 Ball)
Trigger Pull
Single-action
Double-action
Height
Width
Muzzle velocity M1911 230 grain ball
+P 185 grain JHP
Maximum Effective Range
Maximum Range (M1911 ball)
Magazine
1. safety lever (manual), 2. double-action mode with 12.1 lb. trigger
pull, 3. firing pin block, 4. disconnector
Rifling
Safety Features
9
CHAPTER 2
OPERATING INSTRUCTIONS
Action
Reference
WARNING
The Mark 23 incorporates single and double
action modes of operation. Anytime the trigger is pulled with the safety lever in the fire
(down) position and a round in the chamber,
the pistol will fire from either the hammer
down (DA) or cocked position (SA).
2.2 Description: The Mark 23 is a semiautomatic,
magazine fed, recoil operated, double/single-action
pistol, chambered for the .45 ACP cartridge up to,
and including, the commercial +P cartridges.
SECTION I - SERVICE UPON RECEIPT OF MATERIALSECTION II - GENERAL DESCRIPTION
Step
2.1 Initial Inspection. Upon initial receipt, the pistol
is to be inspected to ensure it was received in
proper working order.
1
5
2
3
4
para. 3.7, 3.9
para. 3.4
para. 3.5
para. 3.3
Remove pistol and items
from container
Remove packing material
Check for missing items
Field strip weapon and
inspect for:
Missing parts
Proper assembly
Clean, dry and lubricate
(if necessary)
Assemble
Safety/ function check
6
7
10
CAUTION
A pair of Universal Mounting Grooves located
on the front of the Mark 23 frame allow for a
variety of accessories to be used with the
pistol. Improperly designed or installed
accessories may result in damage to the
Mark 23 mounting grooves and/or the Mark
23. Such damage is not covered under
warranty. Be certain to use only HK Authorized
Accessories and follow installation and
precautions carefully.
NOTE
Accessories designed for the Universal Selfloading Pistol (USP) will not work on the
Universal Mounting Grooves of the Mark 23.
2.3 Operation and Characteristics
A. Double/Single Action - For double-action
(DA), pulling the trigger will cock the hammer
and immediately release it discharging a
chambered round. To fire the first chambered
round in single-action (SA), the hammer must
11
be manually cocked before pulling the trigger.
All shots after the first one will be fired singleaction because the slide automatically recocks
the hammer after each shot.
B. Magazine - The magazine is produced from
sheet steel and has a total capacity of 12
rounds. The rounds are positioned within the
magazine in a staggered arrangement. Rounds
are visible through the viewing holes located
along the back side of the magazine housing.
The viewing holes are marked with numerals
denoting the number of rounds remaining within.
The floor plate can be easily removed for
disassembly and cleaning of the magazine
components.
C. Loaded Chamber Indicator - The Mark 23
pistol does not have a loaded chamber
indicator. The extractor does not act as a
loaded chamber indicator.
D. Decocking Lever - The decocking lever allows
the operator to quietly lower the cocked hammer
without concern of an accidental discharge.
When the hammer is cocked, it may be lowered
safely by moving the decocking lever fully into
the decocking (down) position. The decocking
lever cannot be depressed (and therefore does
not allow the hammer to be lowered) if the
safety lever is engaged. The decocking lever
always springs back into its disengaged (up)
position due to the spring pressure exerted by
the decocking spring.
E. Safety Lever - The safety lever is an
ambidextrous “thumb” lever located on the rear
of the frame. It is actuated by the firing thumb of
the operator. The safety lever blocks the
release of the cocked hammer when it is in the
engaged (up) “safe” position (See Figure 4a).
The safety lever is depressed downward into
the “fire” position (See Figure 4b). The safety
lever is not spring actuated and therefore must
be moved manually from one position to the
other by the operator.
12
left safety
lever
hammer
white dot
left safety
lever
hammer
red dot
Figure 4a “Safe” Position
Figure 4b “Fire” Position
The safety lever cannot be placed in the “safe” (up)
position if the hammer is uncocked (down).
WARNING
The pistol should always be carried with the
safety lever engaged when carried in the
single action mode. While there is a spring
detent to prevent this, the safety lever can be
moved to the “fire” position (down) with a
minimum amount of force. This could happen
during careless handling or during removal
of the pistol from the holster. Always check
the position of the safety lever during
handling.
F. Frame - The front and back straps of the
fiberglass reinforced polymer frame are
checkered to ensure a firm grip, even with wet
hands or under conditions of rapid fire. The
trigger guard is extended, recurved and grooved
to provide a firm grip when using two hands or
gloves. The bottom of the trigger guard is flared
on both sides in front of the magazine release
lever to shield the lever from accidental
actuation.
A threaded insert is molded into the front face of
the trigger guard and the frame is grooved
forward of the trigger guard for attachment of an
accessory such as a laser aiming device or an
illuminator. The frame is a one-piece molded
component with metal inserts (locking insert and
guiding part) cast into the frame during
production. The slide rides on these metal
inserts during operation.
G. Slide Release Lever - This lever is used to lock
the slide open and for disassembling the
weapon. As a slide stop, it is depressed upward
by the magazine follower or the operator’s
finger as the slide travels rearward during recoil
13
or manual operation. The slide release lever
engages the recess visible on the left side of the
slide and is spring actuated. The slide release
spring holds the slide release lever in a
disengaged (down) position until required. As a
disassembly lever, the slide release lever is
removed from the left side of the frame when
the slide is held rearward (see para. 3.3). The
slide release lever can be actuated by the firing
thumb of the right handed operator or the index
finger of the left handed operator.
H. Magazine Release Lever - This ambidextrous,
spring actuated lever holds the magazine within
the grip by engaging in the notch found in the
upper third of the magazine housing.
Depressing this lever with the firing hand index
finger or thumb will allow the magazine to drop
from the grip. The magazine release lever is
shielded from accidental actuation by the flared
trigger guard and the design of the synthetic
frame surrounding the lever.
2.4 Cycle of Operation. Begins with weapon
loaded, hammer cocked, safety lever disengaged.
barrel locking block (locked)
opposing angled
locking surfaces
Figure 5 Firing
firing pin
hammer
A. Firing - (See Figure 5) Pulling the trigger
rearward pulls the trigger bar forward. The
trigger bar pivots the sear actuator upwards
which disengages the firing pin block. At the
same moment, the sear is pivoted out of
engagement from the lower of the two shelves
located on the hammer. The compressed
hammer spring drives the hammer forward into
fi
fi
14
the rear end of the firing pin. The firing pin
strikes the primer of the chambered round. The
propellent is ignited by the primer and propellent
gases are created inside the cartridge case.
The propellent gases drive the projectile down
the polygonal bore which spins the projectile in
a clockwise direction as a means to stabilize the
projectile’s flight.
B. Unlocking - (See Figure 6) The gas pressure
and energy produced by the propellent gases
push rearward on the slide, which is locked to
the barrel by the engagement of the barrel
locking block within the ejection port milled into
the slide. The opposing angled locking surfaces
incorporated into the design of the barrel locking
block and recoil spring guide rod cause the rear
of the barrel to tilt downward as the slide moves
rearward. By the time the slide and barrel have
recoiled approximately 5 mm, the projectile has
left the barrel and the gas pressure within the
chamber has dropped to a safe level. The barrel
locking block then disengages from the slide.
The slide is now free to recoil rearward
independently of the barrel.
slide
recoil spring
guide rod
barrel locking block
(unlocked)
opposing angled
locking surfaces
ejection port
Figure 6 Unlocking
fi
fi
C. Extraction -The empty cartridge case is held
firmly against the face of the slide by the claw of
the extractor as the slide recoils rearward.
D. Ejection - (See Figure 7) -The rim of the
cartridge case strikes the stationary ejector. The
empty case is ejected from the open ejection
port.
15
ejection port
recoil spring
cartridge
case
Figure 7 Ejection
ejector
slide
fi
fi
fi
hammer
E. Cocking - (See Figure 7) - As the slide
continues rearward the recoil impulse is
dampened by the buffer spring. The recoil
spring is compressed and the hammer
recocked.
barrel locking block
chamber
slide
fi
fi
recoil spring
slide face
Figure 8 Feeding
H. Locking - (See Figure 5) -The slide presses the
barrel forward. As it does, the opposing angled
surfaces of the barrel locking block and recoil
spring guide rod pivot the rear end of the barrel
up into engagement with the ejection port in the
slide. The slide is now fully forward and the
new round is ready to be fired.
fi
F. Feeding - (See Figure 8) -The compressed
recoil spring drives the slide forward. If the
magazine is empty, the magazine follower will
lift the slide release to a point where it will stop
the forward progress of the slide. If the
magazine is not empty, the face of the slide will
make contact with the top round in the
magazine. The round will be driven from the
magazine towards the chamber. The tip of the
projectile is guided into the chamber by the
magazine lips until the round clears the
magazine completely. At that moment the claw
of the extractor snaps onto the rim of the
cartridge case as it becomes parallel with the
bore.
G. Chambering - The slide pushes the cartridge
forward until the projectile enters the mouth of
the forcing cone of the bore and the face of the
slide contacts the rear of the barrel locking
block.
16
2.5 Safety Features
A. Safety Lever - This safety blocks the release of the
cocked hammer in the SA mode. The safety lever
is an external, manually operated, ambidextrous
“thumb” lever located on the left and the right side
of the frame further most back from the trigger. The
safety lever must be manually actuated by the
operator. The shaft of the safety lever moves the
sear block into a position where it blocks the
movement of the sear actuator. The sear actuator,
in turn, does not allow the sear to pivot forward and
thus the hammer cannot be released. Engaging the
safety lever also interrupts the function of the
decocking lever and blocks the hammer
mechanically. The safety lever does not restrict the
movement of the slide. The safety lever is held in
either the fire or safe position by a spring detent.
The safety lever cannot be placed in the safe (up)
position when the hammer is down (uncocked).
B. Double-Action Mode - This safety keeps the
hammer in an uncocked condition until the
moment of firing. The double-action mode
operates as a passive safety feature in the
pistol much as this mode of operation would in
17
any DA revolver or pistol. The hammer is left
uncocked until the decision to fire is made. At all
times the firing pin is locked by the firing pin
block until the trigger is pulled. Approximately
12.1 pounds of pressure on the trigger is
required to cock and release the hammer in the
DA mode of operation. The mode of operation
also permits subsequent hammer strikes on the
same chambered round by simply resqueezing
the trigger.
C. Firing Pin Block - This safety prevents the
firing pin from striking the primer when the
weapon is dropped, the hammer is bumped, or
when the slide slams forward. The firing pin
block is located in the slide and blocks the
forward movement of the firing pin. Only when
the trigger is depressed can the sear actuator
push the firing pin block upward against the
downward pressure exerted by the firing pin
block spring. Once the round has been fired and
the slide begins to recoil, the firing pin block is
pushed back down by the firing pin block spring
and engages within the recess provided in the
center portion of the firing pin.
D. Disconnector - This safety prevents the release
of the hammer unless the slide is fully forward
and/or the trigger is reset (released) between
rounds. This important safety prevents serious
malfunctions from occurring, such as “slamfires” (rounds that fire during loading), automatic
fire, or a round being fired out of the battery
(with the breech unlocked). The disconnector
disconnects the engagement of the trigger bar
and the sear actuator. The disconnector is
engaged (operating) after the slide has moved
2mm to the rear. The slide presses the leading
edge of the disconnector down and into
engagement with the trigger bar. When the
slide is fully forward, the leading edge of the
disengaged disconnector resides in a recess
provided in the bottom of the slide.
18
SECTION III - OPERATION UNDER NORMAL CONDITIONS
WARNING
Always clear the pistol before handling it.
2.6 Clearing Procedures
A. The Mark 23 pistol is not considered “clear” or
safe unless:
1. The magazine is removed,
2. The slide is locked to the rear, and
3. The chamber is free of brass or ammunition.
4. The safety lever is set on “safe”.
NEVER ASSUME THE PISTOL IS CLEAR!
B. To Clear the Pistol:
1. Make sure fingers are outside of the trigger
guard and the pistol is pointed in a safe
direction at all times!
2. Decock Hammer or Engage Safety - depress
decocking lever or engage the safety lever.
3. Remove Magazine - depress the magazine
release lever and remove the magazine from
the frame.
4. Open Slide - lock slide open by pulling slide
rearward as you engage the slide release lever
(up). Watch for live round or empty case to be
ejected.
5. Inspect Chamber - inspect chamber for the
presence of a live round or empty case:
a. Visually view chamber through ejection
port.
b. Physically insert finger into chamber
through ejection port and check for
presence of cartridge case in chamber.
c. Remove any live rounds or empty cases
from the chamber or from within the
weapon.
The pistol is now considered “clear”.
2.7 Loading and Unloading the Magazine - (See
Figure 9)
The magazine of the Mark 23 pistol holds 10 rounds
of .45 caliber ammunition in the commercial
magazine and 12 rounds in the Law Enforcement/
Government magazine.
A. Loading the Magazine 1. Hold the magazine in one hand.
19
2. Hold a round between the index finger and
thumb of the other hand with the projectile
pointing towards the palm.
3. Press the rim of the round down against the
front edge of the follower or the top round in
the magazine and slide the round back under
the magazine lips.
4. Repeat steps 1 - 3 until the magazine is full.
The viewing holes in the back of the magazine
allow the operator to confirm the number of
rounds present within the magazine.
WARNING
Forcefully inserting a loaded magazine into
the Mark 23 may cause the pistol’s slide to
close, chambering a cartridge and making
the Mark 23 ready to fire.
When inserting a magazine, always be
certain that the pistol is pointed in a safe
direction with your fingers off the trigger
and outside the trigger guard. Failure to
do so could cause you to unintentionally
fire the pistol, resulting in serious injury
or death.
Figure 9 Loading the Magazine
B. Unloading the Magazine - exert pressure with
the finger on the base of the cartridge case and
push each round forward out of the magazine
one round at a time until the magazine is empty.
2.8 Loading Procedure
A. Administrative Loading - used to initially load
the pistol before it is to be fired.
Method A (Slide rearward, chamber empty)
20
1. Make sure fingers are outside of trigger
guard and pistol is pointed in a safe
direction at all times!
2. Insert magazine firmly into the frame. Tug on
magazine to insure that it is fully seated and
engaged.
3. Depress the slide release lever to release the
slide and to chamber the first round.
4. Engage safety lever or depress decocking
lever.
5. Remove magazine and top off with one
additional round.
6. Reinsert magazine insuring that it is fully
seated.
Method B (Slide forward, chamber empty)
1. Make sure fingers are outside of trigger
guard and pistol is pointed in a safe
direction at all times!
2. Insert magazine firmly into the frame. Tug on
magazine to insure that it is fully seated and
engaged.
3. Retract the slide fully and release. Do not ride
slide forward!
4. Engage safety lever or depress decocking
lever.
5. Remove magazine and top off with one
additional round.
6. Reinsert magazine insuring that it is fully
seated.
B. Tactical Reloading - used to quickly reload
pistol once firing has begun.
Method A (Slide rearward, chamber empty)
1. Make sure fingers are outside of trigger
guard and pistol is pointed in a safe
direction at all times!
2. Keep eyes on target area.
3. Depress the magazine release with finger or
thumb of firing hand to drop magazine.
4. At the same time, retrieve a full magazine with
the non-firing hand and insert firmly into the
frame. Tug on magazine to insure that it is
fully seated and engaged.
5. Depress slide release to chamber first round.
6. Continue firing.
Method B (Slide forward, rounds remaining
in magazine and chamber)
21
1. Make sure fingers are outside of trigger
guard and pistol is pointed in a safe
direction at all times!
2. Keep eyes on target area.
3. Depress the magazine release with finger or
thumb of firing hand to drop partially empty
magazine.
4. At the same time, retrieve full magazine with
non-firing hand and insert firmly into the frame.
Tug on the magazine to insure that it is fully
seated and engaged.
5. Weapon is now back at full capacity without
rendering chamber empty and weapon
useless.
6. Continue firing
2.9 Readying the Pistol for Firing
Disengage the safety lever (if engaged). Red hazard
dot will be visible above safety lever.
WARNING
1. BE SURE OF YOUR TARGET AND WHAT’S
BEHIND IT!Even a .45 caliber projectile can
easily penetrate wood, plasterboard walls, or
a car door, and can travel as far as one mile!
2. Ensure that all parts of your hand and body
are kept away from the muzzle of the pistol
at
all times!
3. Always wear eye and ear protection where
possible when firing the pistol.
4. Whenever the pistol is dropped on a hard
surface landing on the hammer (cocked or
down), it should be sent to the HK Service
Department as soon as practicable to inspect
the sear axle. If the sear axle is bent, it should
be replaced.
2.10 Firing the Pistol
A. Single-action mode (Hammer back/cocked)
Affords operator the best and lightest trigger pull
(≈ 4.8 lbs.) for precise and accurate bullet
placement.
With manual safety disengaged:
1. Aim at the target.
2. Fire the weapon by pressing the trigger straight
22
to the rear with gradually increasing pressure.
3. Engage the safety lever to remain in the singleaction mode once firing is completed.
CAUTION
Single action mode trigger pull is lighter &
shorter than double action mode. Keep your
finger off the trigger & outside the trigger
guard except when firing the
Mark 23.
B. Double-action mode (Hammer down/uncocked)
Provides the operator with a long, heavy (≈12.1
lbs.) trigger pull for the first shot only. Subsequent
shots will be fired in single-action mode as the
slide will automatically cock the hammer after
each round is fired. The double-action mode of
fire is often the preferred mode of fire when
safety during handling and carrying is of greater
concern than first round accuracy.
1. Aim at the target.
2. Fire the weapon by pressing the trigger straight
to the rear with gradually increasing pressure.
3. Depress the decocking lever to lower the
hammer to return to the double-action mode
once firing is complete, or engage the safety
lever to remain in the single action mode.
SECTION IV - OPERATION UNDER UNUSUAL CONDITIONS
NOTE
Unusual conditions are defined as any climatic
condition requiring special maintenance of
the pistol. Perform the maintenance outlined
for the climate that most applies to your
operational area. Refer to paragraph 3.9 for
lubrication instructions.
CAUTION
If extensive corrosion is found and cleaning
does not solve the problem, contact the HK
Service Department.
2.11 Extreme Cold
A. When operating pistol in extremely cold
climates, clean and lubricate the pistol inside at
room temperature if possible.
B. Apply a light coat of LAW (Lubricant, Arctic
Weapons) to all functional parts.
C. To prevent freezing, keep the pistol covered
when moving from a warm to a cold area. This
23
will allow gradual cooling.
D. Always keep the pistol dry.
E. Do not lay a hot pistol in snow or ice.
F. Keep ammunition dry; moisture will cause
malfunctions. Do not lubricate the
ammunition.
G. Always keep snow out of the bore of the barrel.
If snow should get into the bore, clean the bore
before firing using a swab and cleaning rod.
2.12 Hot, Wet Climates
A. Perform maintenance more frequently. Inspect
hidden surfaces for corrosion. If corrosion is
found, clean and lubricate.
B. To help prevent corrosion, remove hand prints
with a cloth. Dry and lubricate the pistol with
CLP/LSA (Cleaner, Lubricant, Protectant).
C. Check ammunition and magazines frequently for
corrosion. Clean the magazine using CLP/LSA
and wipe dry with a cloth. If necessary, clean
ammunition with a dry cloth.
D. Always keep mud out of the barrel. If mud
should get into the bore, clean it before firing
using a swab and cleaning rod.
2.13 Hot, Dry Climates
A. Dust and sand will get into pistol and cause
malfunctions and excessive wear on component
contact surfaces during firing. Keep the pistol
covered when possible.
B. Corrosion is less likely to form on metal parts in
a dry climate. Therefore, lightly lubricate
internal working surfaces only with CLP/LSA.
Do not lubricate external parts of the pistol.
Wipe any excess lubricant from exposed
surfaces. Do not lubricate internal components
of magazine.
2.14 Heavy Rain and Water Operations - All
Climates
A. Perform maintenance in accordance with the
appropriate climatic conditions.
B. Always attempt to keep pistol dry.
C. Always try to drain any water from barrel prior to
firing. Dry the bore with a swab and cleaning
rod.
D. Lightly lube the bore and chamber. Generously
lube internal and external surfaces of the pistol
24
with CLP/LSA.
E. In extreme or prolonged wet or saltwater
conditions, cover serial number and proof mark
on barrel and slide with a temporary protective
coating. These are etched on through the
permanent protective coating on the barrel and
slide and therefore may corrode under these
conditions.
SECTION V - MALFUNCTIONS AND STOPPAGES
2.15 Remedial Action - Remedial Action is the
action performed to remedy an unanticipated
interruption of the pistol’s operation and place the
pistol back into operation.
WARNING
During remedial action, make certain the pistol is pointed in a safe direction at all times.
A. Clear the pistol!
B. Attempt to lock slide.
C. Remove magazine.
D. Inspect chamber.
E. Insert fresh magazine
F. Release slide.
G. Attempt to fire the pistol.
If the Mark 23 fails to fire, return the weapon to the
HK Service Department for service.
25
WARNING
If a round is assembled without powder (a
fault of the manufacturing process), the primer
alone has enough power to propel the
projectile into the bore. A projectile lodged in
the bore may cause damage to the barrel and/
or the pistol if another round is fired and
could cause personal injury. This event is
commonly called a “pop and no kick” or
“squib load” and is characterized by a much
reduced report and little or no movement of
the slide. An alert operator should notice the
occurrence of this event in time to avoid
firing the next round.
Selection and Use of a Holster Selection - When selecting a carrying holster for the
HK Mark 23, it is important to consider the following
points:
1. The holster must not make contact with or actuate
any of the operating controls. This includes the
hammer, slide release, magazine release lever,
and most importantly the safety lever and the
trigger. The design of the holster must also not
actuate these controls when the pistol is carried in,
drawn from, or returned to the holster.
2. The holster should not cause the slide to move
(unlock) when the pistol is returned to the holster.
3. Accommodations must be provided in the holster
for any accessories that might be present on the
pistol.
4. Choose a holster designed for the Mark 23.
Returning the Pistol to the Holster - The HK
Mark 23 must be made “safe” (or cleared) prior to
returning it to the holster. The pistol is considered safe
to return it to the holster when:
1. All fingers are off of the trigger and out of the trigger
guard and;
2. The pistol is “clear” or;
3. The hammer is in the decocked (down) position or;
4. The safety lever is engaged in the safe position
when the hammer is cocked.
WARNING
The pistol must never be returned to the
holster unless the above procedures have
been followed or injury or death could occur.
26
CHAPTER 3
MAINTENANCE INSTRUCTIONS
SECTION I - TOOLS & EQUIPMENT
NOTE
The service life and performance of your HK
Mark 23 is dependent upon the correct
handling and proper care by the operator.
3.1 Operator Tools and Equipment Required. At
a minimum, you will require the following materials
to maintain the Mark 23 pistol and its components:
• Cleaning rod with handle and eyelet
• Long handled nylon brush
• Bronze bristle bore brush (.45 caliber)
• Cotton swabs
• Solvent/bore cleaner/CLP
• Cleaning patches (.45 caliber)
• Rag
CAUTION
Use safety goggles when using solvents and
exercise care if using compressed air.
27
SECTION II - PREVENTATIVE MAINTENANCE (PM)
SERVICE CHECKS & MAINTENANCE PROCEDURES
3.2 General - This PM Service section lists those
required checks and services to be performed by
personnel who operate the Mark 23 pistol. This
section includes the services required to prepare the
pistol for operation, to check the pistol during
operation, and to ensure proper function after
maintenance. Before performing any PM Service
procedures, ensure that the Firearm Service Record
has been updated with the correct round count and
any PM Service procedures documented. If your
equipment fails to operate, refer to the Troubleshooting Table in Section III.
WARNING
Before starting an inspection procedure
CLEAR THE PISTOL! Inspect the chamber to
ensure that it is empty. Do not keep live
ammunition near maintenance /work areas.
NOTE
Before starting any PM Service procedure
ensure that the Firearm Service Record has
been updated with the correct round count
and any PM Service performed documented.
3.3 Disassembly (Field stripping)
A. Pistol
1. Clear the pistol!
2. Depress slide release and allow slide to move
forward.
3. If applicable, remove any mounted accessories.
4. Using the left hand, retract and hold the slide
to the rear approximately 22 mm until the front
end of the slide release is centered on the
recess visible on the left side of the slide (See
Figure 10).
5. With he right hand push the slide release into
the recess on the right side of the frame, lift
and completely remove the slide release from
the left side of the frame.
28
Recess
Slide
Release
Figure 10
Removing or Installing the Slide Release
CAUTION
Hold the recoil/buffer spring assembly in place
while removing the slide from the frame.
6. Remove the slide with barrel and captured
recoil/buffer spring assembly off of the frame by
sliding it forward.
7. Remove the captured recoil/buffer spring
assembly from the barrel and slide by lifting up
on the rear of the guide rod. The entire
assembly can now be lifted out of the slide.
8. Lift the rear of the barrel by the locking block
and withdraw it from the slide.
B. Magazine
12-Round Law Enforcement Magazine
1. Using a blunt pointed instrument depress the
locking detent protruding through the bottom of
the magazine floor plate and hold it there.
2. Place a portion of either hand over the base of
the magazine to control the release of the
magazine spring and locking plate.
3. Slowly slide the floor plate forward off of the
magazine housing.
4. Gradually allow the locking plate and magazine
spring to expand out of the magazine housing.
5. Remove the locking plate, magazine spring and
magazine follower from the magazine housing.
29
10-Round Civilian Magazine
1. Using a blunt pointed instrument depress the
locking insert detente located in the floor plate
and hold it there.
2. Place a portion of either hand over the base of
the magazine to control the release of the
magazine spring and locking insert.
3. With the locking detente still depressed,
squeeze the floor plate locking tabs located on
the right and left sides of the magazine.
4. Gradually allow the locking insert and magazine
spring to expand out of the magazine housing.
5. Remove the locking insert, magazine spring and
magazine follower from the magazine housing.
CAUTION
Beware of the spring tension exerted by the
magazine spring while removing and
installing the magazine floor plate. Keep the
base of the magazine pointed in a safe
direction (away from face and eyes) during
disassembly and assembly.
CAUTION
Operator disassembly of the Mark 23 pistol is
now complete. Only trained HK Service
Department personnel may disassemble the
weapon further.
3.4 Reassembly (From field strip)
A. Magazine
12-Round Law Enforcement Magazine
1. Place the magazine follower onto the end of the
magazine spring having the loop at the end of
the wire on the left side of the follower.
2. Insert the follower and the magazine spring into
the magazine housing.
3. Place the locking plate onto the protruding end
of the magazine spring so that the locking
detent is visible (see Figure 11A).
4. Push the locking plate down into the magazine
housing against the pressure of the magazine
spring and hold it there.
5. Slide the floor plate over the base of the
magazine housing and locking plate from front
to rear making sure that:
a. The floor plate engages the tabs located on
30
magazine spring
floor plate
locking plate
the left and right sides of the magazine
housing.
b. The floor plate is fully seated on the magazine
housing.
c. The locking detent fits within the hole provided
in the floor plate.
d. Check the magazine for proper assembly by
insuring that the follower slides up and down
freely within the magazine housing and with
spring tension. Also check that the magazine
follower rises within the housing to be nearly
flush against the bottom of the magazine lips.
magazine
follower
magazine housing
Figure 11A Assembly of Magazine Follower & Spring
(12-Round Law Enforcement Magazine)
magazine
follower
floor plate
locking insert
magazine spring
magazine housing
Figure 11B 10-Round Civilian Magazine
(Disassembled)
10-Round Civilian Magazine (see Figure 11B)
1. Place the magazine follower onto the
magazine spring with the end of the spring
positioned on the left of the follower.
2. Insert the follower and magazine spring into
the magazine housing.
3. Place the locking insert (on 10-round
magazines) onto the protruding end of the
magazine spring so that the rounded corners
face towards the front of the magazine.
31
4. Push the locking plate down into the magazine
housing against the pressure of the magazine
spring and hold it there.
5. Push the floor plate up onto the base of the
magazine housing until the locking tabs
engage in the sides of the housing. Check to
see if the locking tabs on the floor plate are
securely locked into the housing and the
locking detente on the locking plate fits within
the hole in the floor plate.
6. Check the magazine for proper assembly by
insuring that the follower slides up and down
freely within the magazine housing and with
spring tension. Also check that the magazine
follower rises within the magazine housing to
be nearly flush against the bottom of the
magazine lips.
B. Pistol
1. Insert the muzzle of the barrel through the
large hole located in the front of the slide.
2. Drop the barrel down into the slide and push it
forward until the O-ring engages the slide, the
locking block fits within the ejection port, and
the angled locking surface of the locking block
are visible along the bottom of the slide. The
O-ring will now hold the muzzle tight in the
front of the slide.
3. Install the captured recoil/buffer spring
assembly into the slide so that the front of the
recoil spring guide rod engages in the smaller
hole located in the front of the slide.
4. Align the opposing angled locking surfaces of
the recoil spring guide rod with those located
on the bottom of the barrel locking block.
5. Push the rear of the recoil/buffer spring
assembly forward enough so that the recoil
spring retainer can be engaged on the shelf
provided on the front of the barrel locking
block (see Figure 12).
6. Hold the slide in the right hand with the thumb
holding the rear end of the recoil/buffer spring
assembly in place on the slide (see Figure 13).
7. Hold the frame in the left hand. Position the
rear of the slide above the front edge of the
frame.
8. Draw the slide back onto the frame so that the
rails of the locking insert and guiding part slide
within the grooves in the slide.
9. Retract the slide to the point where the recess
in the left side of the slide is centered on the
hole where the axle of the slide release will go.
32
shelf
barrel
recoil spring
retainer
buffer spring
recoil spring
O-ring
C-clip
threads
10. Hold the slide in this position and insert the
slide release from the left to right into the
frame until it is flush with the side of the frame
and locks in place.
locking block
recoil spring
guide rod
Figure 12 Proper Position for the Captured Recoil/
Buffer Spring Assembly on the Barrel Locking Block
frame
slide
thumb holding recoil/buffer spring
assembly on the locking block
Figure 13 Correct Position for Holding Slide
for Reassembly
NOTE
Operator reassembly of the Mark 23 pistol is
now complete, but not finished without a
safety/function check.
3.5 Safety/Function Check
A. A safety/function check should be performed
anytime the pistol is reassembled. This quick
33
check indicates whether or not the pistol was
properly assembled and with all the components. A properly executed safety/function
check can also reveal many of the more obvious
malfunctions that could occur between the
interactive components of the pistol.
B. Always clear the pistol before performing a
safety/function check! Don’t assume the
pistol is clear!
1. Clear the pistol!
2. Actuate the slide and the operating controls to
insure that:
a. Magazine and catch - the magazine is
held securely in place by the magazine
catch and that it drops free of the frame
when the catch is depressed.
b. Slide - the slide moves freely and without
binding on the frame (with and without a
magazine installed).
c. Barrel - the barrel locking block does lock
fully into battery within the ejection port of
the slide as the slide is closed.
d. Slide Release 1) The slide release does hold the slide
open when retracted while:
a) an empty magazine is in place.
b) the slide release is engaged (pressed
upwards).
2) The slide release does permit the slide to
snap forward when:
a) the slide release is depressed.
b) the slide is retracted without a
magazine installed.
3) The slide release does rebound with
spring pressure.
3. Perform the following safety checks:
nounced stop when moved from “safe” to
“fire” position and back, return the pistol
to the HK Service Department for service.
3) With the pistol unloaded, cock the
hammer and press the safety lever
upward into the safe position. Grasp the
pistol in the shooting position and
squeeze the trigger three or four times. If
the hammer falls, return the pistol to the
HK Service Department for service.
1) With the pistol unloaded, cock the hammer
and depress the decocking lever. If the
hammer does not fall or the decocking lever
does not rebound (upward into its normal
position) with spring pressure, return the
pistol to the HK Service Department for
service.
b. Decocking Lever Test.
1) With the pistol unloaded and hammer
down (uncocked) attempt to press the
safety lever upward into the safe position.
The safety lever should not engage. If the
safety lever engages, return the pistol to
the HK Service Department for service.
2) With the pistol unloaded, cock the
hammer and press the safety lever
upward into the safe position. Attempt to
depress the decocking lever three or four
a. Safety Lever Test.
2) With the pistol unloaded, the hammer
cocked, move the safety lever several
times from the “safe” to “fire” position. If
the safety lever does not have a pro34
times. If the hammer falls, return the
pistol to the HK Service Department for
service.
c. Decocked (hammer down) Test.
NOTE
On the Mark 23 pistol when decocked (hammer
down), the sear is engaged with the hammer at
a rebounded stop position not touching the
rear of the firing pin.
1) With the pistol unloaded, squeeze the
trigger allowing the hammer to cycle in the
double action mode. After the hammer
drops, retain pressure on the trigger. With
the non-firing hand apply pressure with your
finger tips on the rear of the hammer. The
hammer should move forward toward the
firing pin. Release pressure on the trigger
while still retaining pressure with fingers on
hammer. Release pressure on hammer. If
the hammer fails to spring back into the stop
position, return the pistol to the HK Service
Department for service.
35
2) With the pistol unloaded, hammer
uncocked, trigger forward, apply pressure
to the hammer with your finger tips. If the
hammer moves forward to the firing pin,
return the pistol to the HK Service
Department for service.
d. Disconnector and Trigger Test.
1) With the pistol unloaded, cock the
hammer, push the slide rearward
approximately 3/16 inches (2mm) and
hold in that position while squeezing the
trigger. If the hammer falls, return the
pistol to the HK Service Department for
service.
2) With the pistol unloaded, pull the slide
rearward until the slide stop will engage.
Squeeze the trigger and release the slide
forward simultaneously. If the hammer
falls, return the pistol to the HK Service
Department for service.
3) With the pistol unloaded, pull the slide
rearward and engage the slide. Squeeze
the trigger and release the slide forward
simultaneously. Release pressure on the
trigger. If the trigger does not return to its
normal position, return the pistol to the
HK Service Department for service.
Squeeze the trigger and the hammer
should fall. If the hammer does not fall,
return the pistol to the HK Service
Department for service.
4) With the pistol unloaded and the trigger
forward, apply thumb pressure to the
cocked hammer. If the hammer lowers
solely as a result of thumb pressure,
return the pistol to the HK Service
Department for service.
3.6 Function Firing
If any corrective action was accomplished, the pistol
shall be function fired a full magazine prior to being
cleaned and returned to service use.
36
3.7 Cleaning - performed after each firing, or
every twelve (12) months, or after any exposure
to extreme environmental conditions such as
salt, fog, sand, dust, mud, water, etc.
A. Normal Cleaning 1. Clear the pistol!
2. Disassemble the pistol into the major assembly groups.
a. Slide 1) Scrub all internal surfaces of the slide
using the nylon brush moistened with
solvent.
2) Remove all loose fouling from all surfaces
of the slide using a rag and cotton swabs.
b. Recoil/buffer spring assembly - remove
all visible fouling using solvent, a nylon
brush, a rag, and cotton swabs.
c. Barrel with locking block 1) Moisten the bronze bore brush with
solvent and scrub the bore from chamber
to muzzle at least six passes, back and
forth. (Note: Repeat steps 1 and 2 until a
cleaning patch can be pushed through the
bore and remains clean.)
2) Remove the loose fouling using cleaning
patches.
3) Scrub outside surfaces of barrel and
locking block with the nylon brush
moistened with solvent.
4) Scrub the threads of the barrel and O-ring
with the nylon brush moistened with
solvent.
5) Remove all loose fouling using a rag and
cotton swabs.
d. Frame 1) Scrub all internal surfaces where carbon
fouling is visible using the nylon brush
moistened with solvent. Concentrate on
the area normally covered by the slide.
2) Using the rag and cotton swabs, remove all
loose fouling from all areas of the frame.
e. Magazine 1) The magazine is disassembled for
cleaning.
2) Scrub the top of the magazine, concentrating on the follower and feed lips, using
the nylon brush moistened with solvent.
3) Using the rag and cotton swabs, remove
all loose fouling from all surfaces of the
magazine.
37
NOTE
All parts of the HK Mark 23 can be immersed in
any cleaning solvent that it is safe to put your
hands into. Gasoline and other motor fuels are
not authorized cleaning solvents. Avoid cleaning the frame in an ultrasonic cleaner as this can
remove the colored “safe” and “fire” dots.
3.8 Inspection
During and after cleaning the operator should
inspect the pistol and its components for any
irregularities that may cause problems during its
operation. If any potential deficiencies are noted,
they should be corrected immediately and/or
brought to the attention of the HK Service Department for service.
A. Visually Inspect the Pistol and Magazine for:
1. Damaged or missing parts
2. Improper assembly or function
3. Absence of free movement, where applicable
4. Absence of spring tension, where applicable
5. Unaccustomed looseness
6. Parts exhibiting signs of cracks, burrs, dents,
or obvious signs of damage or stress
7. Presence of stops or tactile clicks in controls,
where applicable
8. General overall cleanliness
9. Presence of proper lubrication
10. Presence of corrosion or degradation of
surface finish
11. Rubber hammer spur for cracks or chips
CAUTION
If the rubber hammer spur is badly cracked or
chipped, drop safety could be degraded. Pistol
should be returned to HK Service Department
to replace hammer.
3.9 Lubrication
All metal surfaces of the Mark 23 pistol have a
special surface treatment that resists all types of
corrosion including corrosion resulting from
exposure to salt water. However, this surface
treatment does not reduce friction between parts,
therefore, lubricant must be applied to the pistol.
38
Any type of high-quality, medium weight lubricant
(oil or grease) specifically designed for use on
firearms, such as “Break-Free” (C.L.P.), will work
well on the Mark 23 pistol.
Do not use lubricants that boast of their ability to
penetrate metal as these substances may deaden
primers.
A. Where and how much?
No Lube - (surface is dry and not slippery to the
touch)
• Plastic components
Light Lube - (finger run across surface yields
little or no lube)
• Bore, chamber, and exterior of barrel
• All metal parts
• All internal parts in slide and frame
• Magazine housing and spring
• Recoil/buffer spring assembly
• Sights
• O-ring
Medium Lube - (finger run across surface
yields some lube but lube does not run down
surface when held in a vertical position)
• Barrel locking block
• Slide rails
• All operating controls
• Locking insert and guiding part
• Extractor
Heavy Lube - (Lube runs down surface when
held in a vertical position)
NOTE
No heavy lube is required on the Mark 23
pistol.
Reapply lubrication periodically during firing as it
burns off from the heat. Apply lubricant using a
shaving brush, cotton swabs, patches, or rag. A
spray bottle also works well using compressed air to
circulate the lubricant into all parts and to remove
the excess.
39
SECTION III - ADJUSTMENT OF SIGHTS
Description 1. The mechanical sights supplied with the Mark
23 pistol are comprised of a fixed front sight
post combined with a rear sight with u-shaped
notch of a conventional configuration. Both
front and rear sights are held in place on the
slide within a standard dovetail groove. The
rear sight is also secured with a retaining
screw and is adjustable for windage and
elevation.
2. Both front and rear sights contain white circles
(or cylindrical tritium capsules) that appear as
dots to the operator. One dot is positioned on
either side of the rear sight aperture and in the
center of the front sight post. When the sights
are properly aligned vertically and horizontally,
so are these dots. Thus, the three dots can be
used for rapid acquisition of the sights and
proper sight alignment.
Adjustment - the battle sight zero of the Mark 23
pistol is easily adjusted by moving or replacing
the rear sight.
40
NOTE
All windage and elevation adjustments are
made using only the rear sight.
1. Windage adjustments - to adjust the
horizontal (left and right) impact of the
projectile follow these steps below:
a. Clear the Pistol!
b. Note the index mark on the rear sight and
its relationship to the index mark on the
slide.
c. Loosen the rear sight retaining screw using
a screw driver.
d. With a small hammer and brass or soft
metal drift punch, drift the sight to the:
1) LEFT to move the point of impact to the
left.
2) RIGHT to move the point of impact to the
right.
3) The amount of movement will depend on
the individual shooter and the ammunition
used.
NOTE
Always strike the sight on the sight base, not
on the sight blades.
e. Retighten the rear sight retaining screw.
f. Confirm your battlesight zero by firing the
pistol again.
2. Elevation Adjustments -To adjust the vertical
(up and down) impact of the projectile follow
these steps below:
a. Clear the pistol!
b. Determine the amount of vertical change, in
inches, that is required at 25 meters. Note
the index mark on the rear sight and its
relationship to the index mark on the slide.
c. Loosen and remove the rear sight retaining
screw using a screw driver.
d. With a small hammer and brass or soft
metal drift punch, drift the sight completely
out of either side of the dovetail groove.
e. Note the marking on the bottom of the rear
sight. (The standard sight is unmarked),
f. Select a higher or lower rear sight from
41
Figure 14.
g. Using the brass or soft metal punch and
hammer, install the new sight into the
dovetail groove.
h. Align the index marks of the rear sight and
slide as noted in step b above.
i. Reinstall and tighten the rear sight retaining
screw.
j. Confirm your battle sight zero by firing the
pistol again.
3. Rear Sight Selection - The rear sight is
marked with -6, -4, -2, unmarked, +2, +4, or +6.
This marking represents the amount of vertical
change, in inches, that occurs when that sight is
exchanged with the sight originally installed in
the pistol.
1) To RAISE the point of impact, install a
higher rear sight.
2) To LOWER the point of impact, install a
lower sight.
Example: The pistol is shooting 4 inches high at
25 meters. We want the pistol to shoot dead-on
(point of aim, point of impact). The rear sight
-4
-2
+4
+6
No Marking (Standard)
+2
removed from the pistol is unmarked (standard).
1) Figure 25 shows that the rear sight marked -4
would lower the point of impact two increments,
or a total of 4 inches, from the standard
unmarked rear sight removed from the pistol.
2) The -4 sight would be the correct one to
install. Obtain the exchangeable rear
sight from the kit delivered with the
pistols.
-6
Raise Point of Impact (Inches)
Figure 14
C. Zeroing
1. The battlesight zero of the Mark 23 pistol is set
by the manufacturer using +P 185 grain JHP
ammunition. The pistol is fired from a machine
rest at a target positioned 25 meters from the
Lower Point of Impact (Inches)
42
pistol. The pistol is zeroed point of aim, point
of impact (POA/POI). This means the impact
of the projectile on target will coincide with the
point of aim of the sights at 25 meters.
2. Each individual operator of the Mark 23 pistol
can battlesight zero their pistol to their unique
shooting style by adjusting the sights in
accordance with the procedures in subparagraphs 1 - 3 above.
SECTION IV - TROUBLESHOOTING PROCEDURES
Unserviceable magazine
Dirty or damaged magazine
Incorrect loading procedure used
Improperly assembled
Fouled magazine or pistol
Remove obstruction, clean and lube
chamber/bore
Replace magazine
Clean and lube or replace magazine
Load pistol in accordance with instructions
in operator’s manual
Assemble correctly
Clean and lube pistol and magazine
REMEDY
Obstruction present in chamber
and/or bore
Return pistol to the HK Service Department for service
SYMPTOM/CAUSE
3.11 Operator Troubleshooting Procedures
PROBLEM
1. Round does not feed
2. Round does not chamber
Bent or damaged recoil spring,
buffer spring, or guide rod. Buffer
spring retainer roll pin drift. *
* NOTE
Always inspect the buffer spring retainer roll pin for drift. If not firmly seated and centered in the guide
rod, return to the HK Service Department for replacement.
43
PROBLEM
3. Slide does not lock
fully forward
4. Pistol does not fire
5. Slide does not unlock
SYMPTOM/CAUSE
REMEDY
Clean and lube barrel locking block and
slide
Replace ammunition
Fouled barrel locking block or slide
Damaged or burred slide, barrel
locking block, or recoil/buffer
spring assembly. Buffer spring
retainer roll pin drift. *
Faulty ammunition
Return pistol to the HK Service Department for service
Lubricate pistol in accordance with
instructions in operator’s manual
Little or no sign of firing pin strike
(indent) on primer
Check bore for obstruction and replace
ammunition
Dry component parts or pistol
Faulty ammunition, determined by
short recoil
Return pistol to the HK Service Department for service
Return pistol to the HK Service Department for service
Check for broken or damaged slide,
barrel locking block or recoil/buffer
spring assembly. Buffer spring
retainer roll pin drift. *
44
Broken or damaged extractor
or extractor spring
Pitted or damaged chamber
Fouled or corroded ammunition
Ruptured cartridge case in chamber
Fouled chamber
Return pistol to the HK Service Department for service
Return pistol to the HK Service Department for service
Return pistol to the HK Service Department for service
Replace ammunition
Remove ruptured case, clean and lube
chamber
Clean and lube
REMEDY
Damaged or improperly assembled
component parts
Replace O-ring
SYMPTOM/CAUSE
Damaged or missing O-ring
PROBLEM
7. Operating controls do not
function as described
in operator’s manual
6. Cartridge does not extract
8. Accuracy degradation
45
Position No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
Item Description
extractor
extractor spring
rear sight retaining screw
rear sight, 6.3mm standard (unmarked)
rear sight, 5.5mm (-4)*
rear sight, 5.9mm (-2)*
rear sight, 6.7mm (+2)*
rear sight, 7.1mm (+4)*
rear sight, 7.5mm (+6)*
front sight
firing pin
firing pin spring
firing pin block
firing pin block spring
firing pin retaining pin
extractor pin
slide
barrel
O-ring
recoil spring guide rod
recoil spring retainer
buffer spring
dual roll pin (buffer spring retainer)
buffer spring retainer
spring ring
washer
recoil spring
trigger bar, complete
trigger bar spring
c-clip (decocker)
decocking spring
decocker
roll pin (ejector)
ejector
sear
sear spring
sear actuator
disconnector
sear axle
Part No.
Position No.
roll pin (right safety lever)
right safety lever
sear block
decocking lockout
hammer axle
hammer, complete
hammer rebound spring
hammer strut
hammer strut spring
insert
locking bolt
frame
safety detent
safety detent spring
left safety lever
decocking lever
magazine release pin
magazine release spring
magazine release
slide release spring
trigger
trigger pin
slide release lever, complete
magazine housing (12-rd magazine)
magazine housing (10-rd magazine)*
follower (10 & 12-rd magazine)
locking plate (12-rd magazine)
locking plate (10-rd magazine)*
floor plate (12-rd magazine)
floor plate (10-rd magazine)*
magazine spring (12-rd magazine)
magazine spring (10-rd magazine)*
locking insert (molded into frame)
trigger guard insert (molded into frame)
guiding part (molded into frame)
magazine (12-rd with LE markings), complete*
magazine (10-rd), complete*
Item Description
3.12 Parts Listing for Mark 23 Pistol
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
58A
59
60
60A
61
61A
62
62A
63
64
65
*not pictured
46
215707
215708
215711
215770
215767
215768
215771
215774
215783
215721
215705
215706
215709
215710
986432
986432
215667
215671
986429
215724
215725
215726
986433
215727
929191
215728
215729
215760
215734
927062
214743
215742
986431
215752
215748
215749
215750
215751
215753
Part No.
986430
215744
215754
215745
215738
215772
215739
215740
215741
215731
215732
215976
215746
215747
215769
215766
986432
215737
215775
215733
215735
215736
215763
215778
215672
215779
215781
214853
215780
215673
215782
214821
215668
215670
19
22
18
62
17
Figure 15 Exploded Diagram
HK Mark 23 Pistol
20
21
61
16
14
58
60
5
15
12
13
57
59
56
55
50
47
63
64
23
11
24
26
1
9
25
28
47
48
52
54
27
53
51
49
2
10
8
31
29 30
3
46
4
38
45
44
7
33
36
32
34
35
37
65
42
43
41
39
40
6
CHAPTER
4-
AMMUNITION
The Mark 23 pistol was designed to operate best
using two types of .45 ACP caliber ammunition.
They are:
A. M1911 230 grain Ball
B. Commercially Manufactured 185 grain +P
Jacketed Hollow Point (JHP)
WARNING
The use of incorrect ammunition in the pistol
could result in damage to the pistol and/or
injury to the operator or bystanders
DO NOT USE
• Reloaded, remanufactured, or military surplus
(foreign or outdated) ammunition
• Ammunition loaded in aluminum cartridge cases
• Cracked, split, dirty or corroded cases
• Ammunition assembled with corrosive primer
and/or propellent
• Ammunition assembled with projectile damaged
or pushed into cartridge case past crimp
• Ammunition exposed to oil, grease, water, or
direct sunlight. Remove contaminants if
48
possible before use and cool down ammunition
exposed to direct sunlight or heat. (Exposure to
sources of heat could raise the chamber
pressure of the cartridge above safe limits).
WARNING
Heckler & Koch specifically disclaims any responsibilities for any damage or injury that
should occur because of, or as a result of , the
use of faulty, remanufactured, or reloaded
(hand loaded) ammunition, or of cartridges
other than those for which the pistol was originally chambered for.
NOTE
If after reviewing this manual you still have
questions, please contact your HK dealer or
telephone the Heckler & Koch Customer
Service Department. Please address any
suggested changes or improvements
concerning this manual to HK’s Creative
Services Department.