Heckler And Koch HK Mark23 Operators Manual

1 CONTRACT NUMBER N00164-94-C-0040SW370-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
®
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. 

2
TABLE OF CONTENTS
PAGE
CHAPTER 1 INTRODUCTION..................................................................................................................................................... 4
SECTION I GENERAL INFORMATION........................................................................................................................................ 4
SECTION II PISTOL...

3
SECTION V MALFUNCTIONS AND STOPPAGES.................................................................................................................. 25
2.15 Remedial Action........................................................................................................................ 25
CHAPTER 3 MAINTENANCE INSTRUCTIONS....................................................................................................................... 27
SECTION I TOOLS &...

4
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...

5
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 O-
ring 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...

6 SECTION II - PISTOL DESCRIPTION
1.2  Nomenclature
Figure 1  Left View
1.3  Principle of Operation
A. The Mark 23 uses a modified linkless Browning-
style short recoil system to lock and unlock the
breech.
Figure 2  Right View
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...

7 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....

8 E. Magazine -  holds the cartridges in position for
feeding and chambering.F. Slide Release - holds slide to rear when
engaged;  releases slide when lever is
depressed.
Figure 3  Major Assembly Groups
A. Slide
C. Threaded
Barrel
D. FrameE. Magazine
F. Slide Release accessory
mounting groove
threaded insert for
accessory lockingO-ring
threadsbarrel locking block
flared trigger guard
lanyard loop insert
C-clipguide rodrecoil springbuffer springB. Captured Recoil/Buffer
Spring Assembly
safety
magazine...

9 1.5  Technical Specifications:
Caliber .45 ACP (Automatic Colt Pistol)
System of Operation short recoil, semi-automatic
Locking System Browning system (modified), linklessLength Barrel 5.87 in. (149 mm)
Sight radius 7.76 in. (197 mm)
Pistol 9.65 in. (245 mm)Weight Magazine (empty) 12 or 10 rd. capacity .24 lbs. (.110 kg)
Magazine (w/12 rds M1911 Ball) .81 lbs. (.366 kg)
Magazine (w/10 rds M1911 Ball) .72 lbs. (.327 kg)
Pistol (w/ empty 12 or 10 rd magazine) 2.66 lbs. (1.21 kg)
Pistol (w/ 12 rds M1911...

10SECTION II - GENERAL DESCRIPTION
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.
WARNING
The Mark 23 incorporates single and double
action modes of operation. Anytime the trig-
ger 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).
CHAPTER 2...