From the workbench: A HK4 cautionary tale
Results 1 to 10 of 10
Like Tree14Likes
  • 12 Post By Marine0303
  • 1 Post By hkshooterusp
  • 1 Post By Marine0303

Thread: From the workbench: A HK4 cautionary tale

  1. #1
    Teufelshund Tactical
    Marine0303's Avatar
    Join Date : Feb 2010
    Location : Crozet, Virginia
    Posts : 6,769
    Mentioned
    108 Post(s)

    Default From the workbench: A HK4 cautionary tale

    I've had the great opportunity to offer HK Armorer services for several years (always great to turn something you enjoy into a service for others), and while the legacy HK weapons continue to be the mainstay of the work that makes it across my workbench, I thought I would take a moment to share my observations with the HK4.

    As many of you know, the HK4 was Heckler and Koch's first handgun. Not surprisingly, being that prior experience came from Mauser, that they would start with a pistol based on the Mauser HSC. The "4" comes from the fact that the pistol was designed to be configurable in one of four calibers (.22, .25, .32 and .380), by swapping the barrel and magazine, and in the case of the .22 reversing the breach face, readjusting the firing pin and swapping the extractor. Most I have seen come across my workbench though, have been in .380, and hence the problems.

    The HK4 uses a rather delicate alloy receiver. It simply is not designed to withstand heavy recoil impulses like later HK pistol designs. Additionally, as a blowback weapon, along with the recoil spring, which rides along the barrel, it also incorporates a polymer recoil buffer and metal backing plate. The purpose of the latter is to prevent the tang on the bottom of the slide from recoiling so far to the rear that it actually makes contact with the receiver itself. As you would expect, the more pressure associated with the round fired, the more force imparted into the recoil buffer backing plate and receiver. Then factor in that the original polymer buffers, which are long since out of production, have had decades to degrade. This degradation can be expediated through excessive use, environmental conditions during storage and contact with lubricates used during the cleaning process.

    With all this stated, it should not be surprising that almost all of HK4 pistols that I receive for service have degraded or destroyed recoil buffers and back plates, while many of those have some level of receiver damage as well. Unfortunately, most of these pistols are not sent in for proactive/preventive maintenance, but instead arrive because the owners "went to the range, fired a few rounds, and then the pistol locked up and I cannot remove the slide". Sadly, this is because the degraded recoil buffer was not inspected prior to shooting and when shooting begins, it simply crumbles, the slide impacts the backing plate, destroying it, lodging its remains between the slide and receiver and finally the slide impacts the receiver, chipping and cracking it.

    When I receive the pistol and am able to disassemble the slide from the receiver, this is generally what I find. Note the crumbled remains of the recoil bugger and the bent backing plate inside the slide.



    Note the shiny, chipped and cracked areas in the receiver, above the trigger guard. This is where the slide has over-travelled into the receiver once the recoil buffer and backing plate fail.



    During the full disassembly, I am able to clean areas unreachable otherwise in the pistol, that have all manner of "gunk" build up from decades and then, if the receiver is still serviceable, I replace the recoil buffer with an aftermarket option produced by my friend, Aaron Spleenis. His design, a red buffer, (shown below) is designed to be wide enough to negate the use of the backing plate. This is smart, as the backing plats are almost always destroyed and are no longer available for purchase from HK.



    So, the lesson here is four-fold. First, if you own a HK4, if possible, I recommend not to shoot it in .380. The lesser calibers produce less pressure on the pistol as a whole and the delicate receiver and recoil buffer system. Second, prior to shooting, inspect the condition of your recoil buffer. Make sure that it is not degraded. If it is yellow and begins to crumble at the touch, it is time to replace it. Third, if you need a recoil buffer, contact Aaron at [email protected]. Finally, if your HK4 needs maintenance, give me a shout. Besides being responsive, professional and cost effective, as far as I know, I'm the only guy still qualified, experienced and willing to service these pistols.
    SF,

    James

    Heckler and Koch Certified Armorer (Heckler and Koch)
    Heckler and Koch Pistol, Submachine Gun and Rifle Instructor (Singleton International)

    Owner, Teufelshund Tactical

    Hidden Content
    Hidden Content

  2. #2
    HKPRO PREMIUM PARTNER
    hkshooterusp's Avatar
    Join Date : Aug 2002
    Location : Central Indiana
    Posts : 2,149
    Mentioned
    7 Post(s)

    Default

    Excellent info, a great PSA, if you will. I had an HK4 years ago in .380. The buffer was nearly toast and I never shot it. Being that as it was, and long before I had an interest in collecting anything, I traded it on something else. Should have simply locked it away. With what I learned here I could have sent it off to James for some love.
    Marine0303 likes this.
    I don't "run" my guns or "run" anything on them. Likewise, none of my guns are "platforms". I hold them up, not the other way around.

  3. #3
    AGG
    AGG is online now
    Unrepentant HKHolic
    AGG's Avatar
    Join Date : Feb 2007
    Location : Alabama
    Posts : 29,544
    Mentioned
    147 Post(s)

    Default

    Thanks for the excellent tutorial!!!
    On 26912, is the importer SACO or HK/Arlington?

    Tony

  4. Remove Advertisements
    HKPro.com
    Advertisements
     

  5. #4
    Gets the Shakes if No HK Contact in 24 Hour Period
    Wilhelm's Avatar
    Join Date : Nov 2010
    Posts : 932
    Mentioned
    0 Post(s)

    Default

    Thank you for this excellent information! Does he make buffers for the P9 as well?
    With regards to the P7, there are two classes of people.

    1. Those who know it to be the finest pistol ever produced.

    2. Those who have yet to fire one.

  6. #5
    Teufelshund Tactical
    Marine0303's Avatar
    Join Date : Feb 2010
    Location : Crozet, Virginia
    Posts : 6,769
    Mentioned
    108 Post(s)

    Default

    Quote Originally Posted by AGG View Post
    Thanks for the excellent tutorial!!!
    On 26912, is the importer SACO or HK/Arlington?

    Tony
    Thanks. Arlington, I believe. Its already shipped back to the owner.
    SF,

    James

    Heckler and Koch Certified Armorer (Heckler and Koch)
    Heckler and Koch Pistol, Submachine Gun and Rifle Instructor (Singleton International)

    Owner, Teufelshund Tactical

    Hidden Content
    Hidden Content

  7. #6
    Teufelshund Tactical
    Marine0303's Avatar
    Join Date : Feb 2010
    Location : Crozet, Virginia
    Posts : 6,769
    Mentioned
    108 Post(s)

    Default

    Quote Originally Posted by Wilhelm View Post
    Thank you for this excellent information! Does he make buffers for the P9 as well?
    I do not believe so, but he could and should.
    Lamont likes this.
    SF,

    James

    Heckler and Koch Certified Armorer (Heckler and Koch)
    Heckler and Koch Pistol, Submachine Gun and Rifle Instructor (Singleton International)

    Owner, Teufelshund Tactical

    Hidden Content
    Hidden Content

  8. #7
    Gets the Shakes if No HK Contact in 24 Hour Period
    Wilhelm's Avatar
    Join Date : Nov 2010
    Posts : 932
    Mentioned
    0 Post(s)

    Default

    Thank you for the reply sir!
    With regards to the P7, there are two classes of people.

    1. Those who know it to be the finest pistol ever produced.

    2. Those who have yet to fire one.

  9. #8
    AGG
    AGG is online now
    Unrepentant HKHolic
    AGG's Avatar
    Join Date : Feb 2007
    Location : Alabama
    Posts : 29,544
    Mentioned
    147 Post(s)

    Default

    Quote Originally Posted by Marine0303 View Post
    Thanks. Arlington, I believe. Its already shipped back to the owner.
    Thanks!!!

    Tony

  10. #9
    Gets the Shakes if No HK Contact in 24 Hour Period
    BeachBum's Avatar
    Join Date : Nov 2013
    Location : Northern Virginia
    Posts : 929
    Mentioned
    5 Post(s)

    Default

    Thanks, James, for an excellent writeup. The HK4 is one of those pistols that I have long admired from a distance but somehow never seemed to acquire. The P9S always seemed to take priority. During one of the HK Pro Days that Jim organized, I remember his kinda shaking his head about it and saying that it made for a fine rimfire plinker but that service life of the receiver dropped to just 500 rounds when chambered in .380 ACP.

    Mark

  11. #10
    Unrepentant HKHolic
    mmissile's Avatar
    Join Date : Dec 2006
    Location : Motown
    Age : 63
    Posts : 2,049
    Mentioned
    4 Post(s)

    Default

    The frame broke on mine, 20 years ago. I guessing that's why the HSc is steel.

    "There comes a time in your life, when you walk away from all the drama and people who create it.
    You surround yourself with people who make you laugh. Forget the bad, and focus on the good.
    Love the people who treat you right, pray for the ones who don't. Life is too short to be anything but happy.
    Falling down is a part of life, getting back up is living."

    "If you can't make them see the light, make them feel the heat" Ronald Reagan

Sponsored Links

 
 

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Search tags for this page

hk4 pistol

Click on a term to search for related topics.