KAK Industries Barrels and Nut/Shroud for S&W Model 76 -- notes of first test

[dbquito]

Hello --  A friend suggested I register here to report on this forum what I found with KAK Industries stuff...  (I never use these forum things, so I don't know whatever proper etiquette of what I'm supposed to say/do in writing this topic posting.)

This relates to the Smith & Wesson Model 76 submachine gun with aftermarket barrel of KAK. My gun is a "U" with serial number in the 4000's if that matters.

You can find the KAK Industries products available online at:

https://kakindustry.com/specialty-parts/firearm-platforms/smith-and-wesson

I ordered online on Monday 4/22 and was surprised yesterday (Thursday 4/25) morning to see it had been delivered. (1) Short Barrel, (1) Long Barrel, and (2) of the "S&W Model 76 - Micro Shroud - with rear serrations" (which I sometimes refer to as a Barrel Nut, or Shroud, or whichever, it's both). Total price was just under $400. 

So I had some time yesterday afternoon to play a bit. Here are some notes and observations from first testing:

1) The barrels are not perfect; some people might not be satisfied. The barrel nut is nice and slightly different and seems functional (maybe a bit of issue, but I'm not really sure yet)

2) I suggest you look carefully at my pictures. In particular, look closely at the side-by-side comparion of KAK long barrel with my regular barrel. 

  --  Photos and a video. Link:  https://imgur.com/a/rrPtqyg    if link doesn't work, let me know by replying to this.

  --  There are various general 'what's it look like' photos and detailed photos. Half way through the photos there's a video showing gun running with "crap" ammo.

  --  Toward the bottom end of the photos are the "size issue" detail photos which compare the KAK Long barrel (which I have not tested) with it side-by-side to the barrel I usually use (which I assume is a factory barrel). Those are the photos you might wish to inspect carefully. 

3) I have only tested the short barrel so far. I have only tested two types of ammo. This is all preliminary initial testing observations -- DON'T TRUST ME ON THIS! -- it's all jsut my first quick impression.

4) First test of short barrel was not good. With 147 grain brass case Winchester brand new ammo, there were moderate cycling problems. With 115 grain aluminum case "crap" ammo, it almost always failed to cycle. It had failure to extract or failure to eject along with insufficient bolt travel for sear thing to catch the bolt (in semi-auto). Inspection of aluminum cases showed mark of extractor not far enough forward to grab around the rim well, plus some popped primers -- it seemed clear that the case was slightly forward of proper position, therefore leaving slight gap between bolt face and bottom of case. 

5) Over an hour or two of screwing around with the thing, testing, whacking, twisting, cleaning, lubing, etc., I gradually improved the cycling functioning. Finally it got working well enough to eat several full magazines of 115 gr aluminum crap ammo without any problems.

  --  I think the gun gets finicky about ammo when using the KAK short barrel

  --  Solution was 1) everything well cleaned and lubed; and 2) apply force to seat the barrel as tightly as possible (and tighten the nut with force). 

6) After looking carefully and comparing to my other barrel and playing around, it seems to me very likely that the root cause of all this relates to imperfect barrel length:

  --  with round in the chamber, consider the distance from (A) the base/bottom of the case to (B) the barrel 'ring' seating surface. That distance is too short with the KAK barrel.

  --  That distance could be too short due to chamber depth (too deep), or due to length of barrel from rear end to the ring seating surface (too short). I am fairly sure it's the barrel length and not the chamber head spacing -- saying that length is too short is the same as saying the position of the ring on the barrel is too far aft.

7) ... so with well cleaned and lubed gun, perfect shaped and greased magazine lips, and the tightening the heck on the barrel nut, the thing seems to be ok. BUT there is still probably a tiny gap between the bolt face and the bottom of the case which makes it fussy.

I will check back for replies to this. Feel free to comment back to me.  Give me other thoughts/ideas that I'm missing or tell me if I'm wrong in my thinking.  

Please note your suggestions as to how I should handle this. I suppose I will do further testing and more careful measuring and then contact KAK about it.  

 

[Rekraps]

23 hours ago, dbquito said:

Hello --  A friend suggested I register here to report on this forum what I found with KAK Industries stuff...  (I never use these forum things, so I don't know whatever proper etiquette of what I'm supposed to say/do in writing this topic posting.)

This relates to the Smith & Wesson Model 76 submachine gun with aftermarket barrel of KAK. My gun is a "U" with serial number in the 4000's if that matters.

You can find the KAK Industries products available online at:

https://kakindustry.com/specialty-parts/firearm-platforms/smith-and-wesson

I ordered online on Monday 4/22 and was surprised yesterday (Thursday 4/25) morning to see it had been delivered. (1) Short Barrel, (1) Long Barrel, and (2) of the "S&W Model 76 - Micro Shroud - with rear serrations" (which I sometimes refer to as a Barrel Nut, or Shroud, or whichever, it's both). Total price was just under $400. 

So I had some time yesterday afternoon to play a bit. Here are some notes and observations from first testing:

1) The barrels are not perfect; some people might not be satisfied. The barrel nut is nice and slightly different and seems functional (maybe a bit of issue, but I'm not really sure yet)

2) I suggest you look carefully at my pictures. In particular, look closely at the side-by-side comparion of KAK long barrel with my regular barrel. 

  --  Photos and a video. Link:  https://imgur.com/a/rrPtqyg    if link doesn't work, let me know by replying to this.

  --  There are various general 'what's it look like' photos and detailed photos. Half way through the photos there's a video showing gun running with "crap" ammo.

  --  Toward the bottom end of the photos are the "size issue" detail photos which compare the KAK Long barrel (which I have not tested) with it side-by-side to the barrel I usually use (which I assume is a factory barrel). Those are the photos you might wish to inspect carefully. 

3) I have only tested the short barrel so far. I have only tested two types of ammo. This is all preliminary initial testing observations -- DON'T TRUST ME ON THIS! -- it's all jsut my first quick impression.

4) First test of short barrel was not good. With 147 grain brass case Winchester brand new ammo, there were moderate cycling problems. With 115 grain aluminum case "crap" ammo, it almost always failed to cycle. It had failure to extract or failure to eject along with insufficient bolt travel for sear thing to catch the bolt (in semi-auto). Inspection of aluminum cases showed mark of extractor not far enough forward to grab around the rim well, plus some popped primers -- it seemed clear that the case was slightly forward of proper position, therefore leaving slight gap between bolt face and bottom of case. 

5) Over an hour or two of screwing around with the thing, testing, whacking, twisting, cleaning, lubing, etc., I gradually improved the cycling functioning. Finally it got working well enough to eat several full magazines of 115 gr aluminum crap ammo without any problems.

  --  I think the gun gets finicky about ammo when using the KAK short barrel

  --  Solution was 1) everything well cleaned and lubed; and 2) apply force to seat the barrel as tightly as possible (and tighten the nut with force). 

6) After looking carefully and comparing to my other barrel and playing around, it seems to me very likely that the root cause of all this relates to imperfect barrel length:

  --  with round in the chamber, consider the distance from (A) the base/bottom of the case to (B) the barrel 'ring' seating surface. That distance is too short with the KAK barrel.

  --  That distance could be too short due to chamber depth (too deep), or due to length of barrel from rear end to the ring seating surface (too short). I am fairly sure it's the barrel length and not the chamber head spacing -- saying that length is too short is the same as saying the position of the ring on the barrel is too far aft.

7) ... so with well cleaned and lubed gun, perfect shaped and greased magazine lips, and the tightening the heck on the barrel nut, the thing seems to be ok. BUT there is still probably a tiny gap between the bolt face and the bottom of the case which makes it fussy.

I will check back for replies to this. Feel free to comment back to me.  Give me other thoughts/ideas that I'm missing or tell me if I'm wrong in my thinking.  

Please note your suggestions as to how I should handle this. I suppose I will do further testing and more careful measuring and then contact KAK about it.  

 

 

First of all, welcome to the Forum! We (mostly) love it when other people experiment with aftermarket parts and then report their findings on this site. this is especially true with regards to the S&W M76, as the two primary sources for spare parts are now out of business. Personally, I was hoping for a better AAR, but alas no. 

The "U" preface to the SN is correct, as most if not all of these guns were manufactured for non-military use (commercial/police etc). About 6000 of the guns were manufactured with many being destroyed in the 9/11 attack (NYPD kept many M76's in the WTC basement).  

You may want to contact Brian Miles (fellow forum member) as he has manufactured custom stock adapters that allow you to affix a sturdy, temporary stock to the gun so you can shoot it with confidence. 

As for me, I'm lucky to have obtained several spare bolts and barrels while they were still available. 

Again, welcome and keep-a-posting!

Watch out for GotUzi though, he can be grumpy. 

[Rekraps]

Also, custom integral suppressors are avialable through Shaw Armament Systems (678.915.2075). They look great, function great and make shooting fun!