Heckler & Koch HK4 Pistol

General Information

The HK 4 (P11 in German military issue) pistol is from the German firm of Heckler and Koch, GmBH. Introduced in 1967, and now out of production (as of 1984 according to the Blue book of Gun Values 13th ed.), it is a large sized pocket pistol, designed to interchange between .22 LR, .25 ACP (6.35mm), .32 ACP (7.65mm) and .380 ACP (9mm Kurz), (8 rounds each except .380 for which the mag capacity is 7) by replacing only the barrel and magazine.

Much of the markings are the same as for the P7 guns -- look here.

H&K HK4 Pistol

HK4 in .22, .25, .32, .380
HK4 Internal Function

H&R catalog from 1971 (page 37)

H&R Commemorative Pistol Set

H&R is pleased to introduce a Commemorative Pistol
Set in honor of its 100th anniversary.  Only a limited
number of these semi-automatic pistol sets have been
produced in serial number sequence from HR 1 to HR 2000.
The set consists of a double action pistol with
interchangeable matched barrels and magazines in .380
caliber and .22 caliber long rifle.  A distinctive gold name
plate and gold trigger accent each pistol.  Matched
barrels are identified with the pistol's serial number.  Each
pistol set is packaged in a custom fitted, velvet lined,
wooden presentation kit with lock and key and will be a
welcome addition to any sportsman's collection of
limited production sporting arms.


Calibers: .380 auto. (9mm short) and .22 long rifle.
Capacities: .380 auto. 8 shots. .22 long rifle 10 shots.
Grips: Black checkered grips.
Barrel Length: 3 1/2".
Overall Length: 6".
Weight: 24 oz.
Action: Single and double. Semi-automatic.
Sights: Fixed front site.  Rear sight adjustable for windage.
Finish: Blue/black with gold name plate and gold trigger.

Commemorative Pistol Set  $160.00

Manual & Library

HK4 User's Manual (PDF File)

An Article on the HK4 by By James Bardwell

Proof Houses 

HK enthusiasts and books will tell you that HK only uses one Proof House, the Ulm, Germany.  Here are images of two .7.65mm barrels, one proofed at Ulm (with stag horn on left) -- the other not!  Early HK4 barrels were not proofed at Ulm.



One area of complication and confusion for the otherwise simple HK4 are its extractors.  There are either two, three, or four different styles depending on who you believe.  I don't know who is correct, so until I do I can only offer this information without explanations.  This is under construction.

The Bardwell article (above) says "The manual speaks of having to change extractors between calibers, but my pistol has a "universal extractor" and requires no changing, so I will assume that was a very early feature, and not cover it. If yours came with multiple extractors you will need to interchange them or get a universal one."

This is from gun #4210X that was made in 9/70.  Note the orange fill on the barrel, but the magazine was all black.

This extractor is labeled, and I would guess is the "old" style

e-gunparts.com offers four different types -- .22 & centerfire, both in "old" and "new" styles.  These are the two "new" style, don't know which is which.


1 Slide (Note #1 Below)
2 Extractor (Note #1 Below)
3 Set Bolt 
4 Compression Spring
5 Rear Sight
6 Safety
7 Recoil Spring (Note #1 Below)
8 Barrel (Note #1 Below)
9 Cylinder Head Screw (Note #1 Below)
10 Face Plate
11 Firing Pin Spring (Note #1 Below)
12 Firing Pin (Note #1 Below)
13 Plunger Spring (Note #1 Below)
14 Plunger
15 Stop Pin
16 Barrel Clamp
17 Barrel Clamp Cylindrical Pin (Note #1 Below)
18 Ejector (Note #1 Below)
19 Ejector Spring (Note #1 Below)
20 Sear (Note #1 Below)
21 Spring Support
22 Drag Spring
23 Disconnector Spring
24 Disconnector
25 Hammer
26 Buffer Plate (Note #2 Below)
27 Buffer (Note #2 Below)
28 Elbow Spring (Note #1 Below)
29 Trigger (Note #1 Below)
30 Trigger Cylindrical Pin
31 Trigger Bar
32 Ejector Cylindrical Pin
33 Hammer Pin (Note #1 Below)
34 Receiver
35 Magazine Catch Cylindrical Pin
36 Spring Rod
37 Mainspring (Note #1 Below)
38 Magazine Catch
39 Grip
40 Grip Screw, Countersunk, Lens Head (Note #1 Below)
41 Magazine Assembly 
42 Magazine Bottom (Note #1 Below)
43 Follower
44 Follower Spring
45 Locking Plate Assembly

Some of these parts are still available at e-gunparts.com
If they have them, they will be cheaper than from me.

Note 1:  As this is written (JAN-2004), I have these parts available

Note 2: Part 27 the Buffer is was not available for a while, but now can be bought at Gun Parts Corp.

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