Two Rounds on a Single Trigger Pull AK-47

[milrifle]

My wife bought her a CAI imported Serbian made AK-47 copy at a gun show a while back. Today, we were trying out some reloads using the Lee 309-155 over 18gr of RL-7 and a CCI LR primer. When she pulled the trigger, much to her surprise, she sent two rounds downrange. Upon inspecting the case, I found the primer was just barely dented on that second round. My first thought was that the disconnector had failed and the hammer had ridden up the back of the bolt. I used to have a friend with an AR-15 that would go full auto without the automatic sear if it were put into what would have been "Auto" position on an M-16. I thought maybe the same thing had happened with the AK. But on the other hand, it may have just been the firing pin slamming into the primer as the bolt went home. What do you think?

[blaser.306]

The RCMP (Royal Canadian Mounted Police) Here in Canada Released a statement regarding an SKS that was imported I believe last year, it came from the Tula armory or one other I will try to find out more. At any rate it was imported and sold into the hands of a sport shooter that soon discovered that it was indeed full auto. The inspection paperwork for subsequent guns even shows pictures of what the fire controls look like with and without the semi auto disconnector ! I will see if I can locate any of the articles.
Inspection Protocol for SKS Carbines

General

1. This concerns the inspection of certain Russian made SKS carbines to determine if they are susceptible to firing in the full automatic mode.

2. The protocol is designed to be quick and simple and not involve the discharge of live ammunition. While revealing obvious potential for full automatic fire, there may be some conditions not detectable through this protocol. Suspect firearms should be isolated for more detailed testing.

3. The full automatic fire issue addressed by this protocol is caused by deficiencies in the trigger mechanism and is not related to previously reported instances caused by hardened grease or other foreign materials embedded in the bolt and interfering with the free movement of the firing pin.

4. One sample was inspected in October, 2014 which would fire only in the full automatic mode, was prone to shock discharge, and had an incomplete safety switch mechanism. Discharge of the carbine could be initiated simply by following the normal loading and cocking sequence. The full automatic fire capability could be migrated from one SKS carbine to another by moving the trigger mechanism thus establishing the problem lies solely in the trigger mechanism.

Scope

5. This protocol applies to Russian made SKS carbines manufactured in either the Tula or Izhevsk arsenal. These carbines are identified via the manufacturer's logo found on the upper rear surface of the receiver cover. Typical markings for the two main arsenals where the SKS carbine was manufactured are illustrated in figure 1 and figure 2. Note that the exact nature of the arsenal marks varies slightly from year to year.

Figure 1: Izhevsk arsenal marking

Figure 1: Izhevsk arsenal marking

Figure 2: Tula arsenal marking

Figure 2: Tula arsenal marking

6. This protocol applies to SKS carbines having the later (post 1951) simplified version of the trigger mechanism installed. The differences are depicted in figure 3.

7. The later version of the SKS trigger mechanism has an enlarged inspection hole (a); does not have the pin holes for mounting the semiautomatic disconnector (b); and the semiautomatic disconnector (c) is absent.

Figure 3: early (below) and later (above) SKS trigger mechanism

Figure 3: early (below) and later (above) SKS trigger mechanism

The Inspection Protocol

8. The inspection protocol is detailed in the table below. The same protocol is attached as Appendix A in a checklist format.


STEP

PROCEDURE

1 Prove the SKS carbine unloaded.
2 Degrease the SKS carbine as required.
3 Apply the safety switch and verify that the carbine cannot be discharged by pulling the trigger.
4 Verify the Russian origin of the SKS carbine.
5 Dissassemble the trigger mechanism and verify the presence of the later version of the trigger mechanism.
6 Reassemble the trigger mechanism.
7 Release the magazine to permit free movement of the bolt and bolt carrier.
8 Cock the mechanism gently restoring the bolt carrier to the forward and locked position.
9 Pointing the carbine in a safe direction, fire the mechanism, and keep the trigger pulled fully to the rear. A distinct "click" should be audible as the hammer falls forward.
10 Re-cock the action manually releasing the bolt carrier at the rearmost point permitting the bolt and bolt carrier to move without interference to the forward and locked position under the power of the return spring.
11 Fully release the trigger and immediately pull the trigger to the rear again. If the "click" of the hammer fall is heard, the firearm is operating in the semiautomatic mode. If no "click" is audible and there is no appreciable resistance to the rearward movement of the trigger, the carbine is most likely operating in the full automatic mode.
12 Carbines which appear to be operating in the full automatic mode are to be quarantined pending further testing.

Follow-up

9. The results of SKS carbine inspections are to be reported to the CFO office in the province or territory where the test was conducted.

10. Questions about the test protocol and related procedures are to be directed to the CFO's office.

Murray A. Smith
Manager, Specialized Firearms Support Services
RCMP Canadian Firearms Program

Appendix A

SKS Carbine Test Protocol

Serial number
Date of inspection
Business name
Name and signature of inspector
Comments


STEP

PROCEDURE

RESULTS and COMMENTS

1 Prove the SKS carbine unloaded.
2 Degrease the SKS carbine as required.
3 Apply the safety switch and verify that the carbine cannot be discharged by pulling the trigger.
4 Verify the Russian origin of the SKS carbine.
5 Dissassemble the trigger mechanism and verify the presence of the later version of the trigger mechanism.
6 Reassemble the trigger mechanism.
7 Release the magazine to permit free movement of the bolt and bolt carrier.
8 Cock the mechanism gently restoring the bolt carrier to the forward and locked position.
9 Pointing the carbine in a safe direction, fire the mechanism, and keep the trigger pulled fully to the rear. A distinct "click" should be audible as the hammer falls forward.
10 Re-cock the action manually releasing the bolt carrier at the rearmost point permitting the bolt and bolt carrier to move without interference to the forward and locked position under the power of the return spring.
11 Fully release the trigger and immediately pull the trigger to the rear again. If the "click" of the hammer fall is heard, the firearm is operating in the semiautomatic mode. If no "click" is audible and there is no appreciable resistance to the rearward movement of the trigger, the carbine is most likely operating in the full automatic mode.
12 Carbines which appear to be operating in the full automatic mode are to be quarantined pending further testing.

[DCM]

Does the firing pin move freely in the bolt?

[nhrifle]

Is the fire control group semi auto or does it have the original military parts in it? Remove the bolt from the carrier and make sure the firing pin doesn't stick in the "fire" position as this can cause a slam fire.

If I had to make a guess as to what happened, I would bet she experienced bump fire, where the recoil drives the rifle into the trigger finger and causes another round to go off. Some of the trigger groups put into import AKs to make them legal have such a light pull this is quite easily accomplished.

[milrifle]

The rifle is only semi. I'm not familiar with how the full auto one looks inside, but the safety has only two positions and passes a typical functional check in that with the trigger held to the rear and the action cycled, there is a "clunk" heard when the trigger is released and the disconnector releases the hammer and the sear catches it.

The firing pin does appear to move freely. It is certainly not stuck in the forward position. It does have a minute amount of drag on it, but like I say, it's not stuck in that position.

I had considered she might have bumped the trigger, but the primer on that second round did not have the deep impression of the firing pin that all the others have. It is barely dented. If she had pulled the trigger a second time, the primer would have the same firing pin impression as the others.

[blaser.306]

I tried to get the pics to load but would not, If you go to www.rcmpsksprotocol (http://www.rcmpsksprotocol) that will have pics with and without the semi auto disconnector and pin hole locations to be looking for.

[milrifle]

One other thing. It only did it the one time. We shot it several more times with no further incident (Although with never more than 5 rounds in the mag).

[aspangler]

A high primer can cause a slamfire. That may be what happened. I have seen a lot of the cheap ammo have high primers. Just sayin'.

[gew98]

Why all the allusion to the SKS ?. Any semi - especially the AK if it has a defective sear and or disconnector will cause a the hammer to drop when the bolt 'rams' home as it lets the hammer jump out and bammo. I have seen and handled import chinese SKS rifles with firing pins frozen with grease go full stupid when fired. I have experianced AR's and AK's with very worn internals that allowed full auto "type" fire of a less than controllable type. Replace those bits and you are good to go. Now I did see one type 68 SKS in a pile of imports at a show in PA 25 years ago .... could not believe it but it was what it was and walked out the door for less than $100 real quick .

[milrifle]

The rifle is brand new. Less than 100 rounds through it.

[1911cherry]

Yep sounds like a bump fire, a faulty sear, or trigger group wouldn't just act up once.

[gew98]

The rifle is brand new. Less than 100 rounds through it.

Brand new or not...it is an AK clone with likely less than quality fit parts . The AK is a bullet hose of peasant proportions. Such issues are not as rare as you might think with the semiauto US import variety.

[Petrol & Powder]

Without any pictures or other information I would vote that it's a firing pin problem. In fact, likely a lot of grease or other crud inside the bolt. The shallow firing pin strike on the second round seems to confirm the hammer is not striking the firing pin on the second shot but the pin is being held forward when the bolt closes.

[Multigunner]

I'll have to field strip my Romainiah AK to examine the pin and whether it has any method of preventing the firing pin from being driven forwards by inertia or stuck in place by fouling.
The AK bolt is a turn bolt loosely base on the M1 Carbine or Garand bolts. The Garand can have slam fires if the firing pin is damaged by contact with the rear of the receiever if a too hot round causes it to open too far and too fast.

Milspec primers aren't so easily set off by a light strike, sporting cartridge primers are more sensitive and more subject to slamfires and doubling.

[Lead Fred]

Its an AKS not an AK-47

Change primers to CCI 34 (LR) CCI 41 (SR), and watch your slam fires go away.

Mrs Fred's SKS has never had a slam fire, nor has the M1, M1a, AR-15, or any other semi-auto, but then Ive only ever used hard primers.

[1johnlb]

+1 on changing primers.

Floating firing pin and a thin primer cup equals Slamfires.

[milrifle]

Thanks guys. I'm leaning toward thin primers or stuck firing pin.

Thanks again. I appreciate all of your thoughts.

[HATCH]

All bolts are f/a on any of the ak style rifles. Its not illegal

Your issue can be one of a couple things.

Binding fire control group
Weak disconnect spring
Dirty firing pin channel

I have never shot reloads in my ak rifles but only one manufacturer made a spring loaded firing pin.
I suppose it is possible that you are getting a slam fire.

[Alexn20]

do you have a 3rd pin on that receiver?
123919

Also take a look at your sear and disconnector. Many rifles just modify the full auto disconnector to a semi auto:
123920


Based on your comment "The primer on that second round did not have the deep impression of the firing pin that all the others have. It is barely dented." I would say this was most likely a slamfire. Be careful and make sure that muzzle is always downrange!!

[milrifle]

Alexn20,

It does not have the third pin hole shown in your photo and the disconnector is like Type 1 in your diagram.

[GoodOlBoy]

Let me ask you a VERY basic question. How much cosmoline did you scrub outa that rifle? Did you take it down in a hot shower and REALLY scrub it out? I had a SK way back when that was full auto firing at every third trigger pull. Turned out no matter how much I scrubbed until I got it in a hot shower and stripped it FULLY I didn't get all the cosmoline out and the freakin thing would full auto or burst fire off and on. Afterwards it behaved like it should. No need to go so far afield to find the answer folks, sometimes it's a basic problem.

GoodOlBoy

[milrifle]

There was no cosmoline in it. It was clean as a whistle. Everything in it appears newly manufactured.

[robertbank]

If it only happened once I would go with a bump fire. Easy enough to do. Try bump firing the gun next time you are at the range. I am sure it won't be hard to duplicate.

Take Care

Bob

[GhostHawk]

http://www.rcmp-grc.gc.ca/cfp-pcaf/rep-rap/images/image03.jpg

This is the picture that you guys were talking about.

Although I really think there probably is nothing wrong with the rifle that a good cleaning wouldn't fix.
A little education normally helps as well.

Also if you don't know what a bump fire is you don't know how to prevent it.

So my advice, take the person that it happened to, give them a good SKS or AK, teach them what bump fire is and how to not let it happen accidentally. And then take that rifle apart and make sure it has all the right parts in the right places and that they are clean.

[milrifle]

It looks nothing like that. Is that an SKS? Been a while since I looked in one. This is a civilian semi-auto AK and looks very much like the photo in post #19.

By "Bump Fire", I assume you mean it fired because the firing pin struck the primer as the bolt was shoving the next round into the chamber similar to the way an M-3 or other open bolt sub-machinegun works. That is certainly a possibility, but I'm leaning toward the reason being an overly sensitive primer, not a dirty rifle. There is and never was any cosmoline. It had only fired less than 50 rounds since brand new. The firing pin slides easily back and forth inside the bolt. It won't slide due to its own weight, but probably only because of the viscosity of the oil on it. It does easily slide back and forth if you shake the bolt in your hand. I don't disagree that it may have been a "Bump Fire", if I understand the definition properly, but I'm not sure how I would duplicate one on demand.

[robertbank]

It looks nothing like that. Is that an SKS? Been a while since I looked in one. This is a civilian semi-auto AK and looks very much like the photo in post #19.

By "Bump Fire", I assume you mean it fired because the firing pin struck the primer as the bolt was shoving the next round into the chamber similar to the way an M-3 or other open bolt sub-machinegun works. That is certainly a possibility, but I'm leaning toward the reason being an overly sensitive primer, not a dirty rifle. There is and never was any cosmoline. It had only fired less than 50 rounds since brand new. The firing pin slides easily back and forth inside the bolt. It won't slide due to its own weight, but probably only because of the viscosity of the oil on it. It does easily slide back and forth if you shake the bolt in your hand. I don't disagree that it may have been a "Bump Fire", if I understand the definition properly, but I'm not sure how I would duplicate one on demand.

I will try to describe bump firing this way. The shooter leaves his/hers trigger finger on the trigger. As the rifle recoils backwards and forwards the trigger finger remains on the trigger, the sear resets under recoil and the trigger finger activates the trigger again and the gun fires. You can make an SKS sound like it is firing on full auto and empty a 10 round mag in a hurry simply by using this method of firing. I suspect that is what happened. The shooter doesn't hold the trigger back but allows the trigger itself to reset. The secret is not to allow your trigger finger off the trigger.

Others feel free to describe it better than I have.

Take Care

Bob

[1johnlb]

I found the primer was just barely dented on that second round.

OP's statement clearly rules out bumpfire. Bumpfiring still causes normal primer strikes.
This is bumpfiring just highly controlled.
https://www.youtube.com/watch?v=GIC8SMttjjo

Slamfires happen on semi auto because of a floating firing pin. When the bolt is closing after racking another round they have the tendency to strike the primer when it comes to a stop in the chamber. If you have never noticed it just try taking out a round after its been racked at full force , many will have lite strikes from the pin.


It won't slide due to its own weight, but probably only because of the viscosity of the oil on it

This excess of oil can also cause slamfires. I exsperienced it in my ar15 because of oil , for the lack of a better word, hydrolocked the fire pin in the foward position causing it to protrude thru the bolt hitting the primer and prematurely firing the next round. I simply wiped the oil from bolt and pin and the slamfires stopped.

I have also had the problems some are talking about with the sks's. Cosmoline in the firing pin canal had hardened and the firing pin would at times stick foward and empty the clip. Needless to say it was fun but unpredictable and definatly not legal and can be considered full-auto, if you got the wrong agent on a bad day.

[milrifle]

OK guys. With that definition, it is NOT a "Bump Fire". I believe it to be what 1johnlb is calling a "Slam Fire".

This gun is too new for me to have thought much about it, but I have certainly seen primers dimpled by firing pins upon bolt closure. My AR-15 will do it every time. I'm not sure about my Garand or M1 Carbine, but it wouldn't surprise me if they all did it. However, I have never had one go off from those tiny dimples. This one certainly did though.

[HATCH]

op -> http://www.akfiles.com/forums/showthread.php?t=34571

[Powder Burn]

I have a similar M70 OPAP. When new, before I shot it, I noticed the firing pin would not easily move back and forth in the bolt. Took bolt apart. Which means you have to punch out a pin in the bolt to get at the firing pin. Thing looked great on the outside, however, the inside had grease buildup on the firing pin shaft. After cleaning, the firing pin could be moved without any drag. My money is on the internal bolt grease. I believe there are videos on utube that will show you how to remove the firing pin. 2nd item would be to check for burrs on the bolt/firing pin hole.

[milrifle]

Interesting link, Hatch. Thanks for posting that.

Here is a photo of the primer with the shallow dimple.


124043

[1johnlb]

Is that a cci large rifle or pistol primer?

[Multigunner]

Here is a photo of the primer with the shallow dimple.


Click image for larger version. Name: primer.jpg Views: 2 Size: 24.5 KB ID: 124043

Thats exactly how every light strike I've noted on unfired ejected rounds from both my AK and SKS looked.
The SKS made even deeper strikes if I single loaded a cartridge and let the bolt fly forward to close.
I always used milspec ammunition and none of these slam fired, but the dents were sometimes deep enough that I wondered why they hadn't gone off.

[milrifle]

It's a CCI Large Rifle primer

[historicfirearms]

Try the mil spec primers next time, they are made specifically for rifles with a floating firing pin. Also, it's imperative that you seat primers below flush for any semi auto rifle. By the picture, it appears that yours was, but just throwing it out as a possibility.

[john hayslip]

Bought a Chinese Tokarev pistol one time that did the same thing. By the time we got the trigger to where it wouldn't offend it weighed about 10 pounds pull and I got rid of it.
Were you shooting reloads??

Nonte's book rightly says that if you load the cartridges faster than the weapon is designed for you can override the sear and make one full automatic on occasion.

Had friend at one time who liked to reload blue pills. He had a Winchester 100 in 308 that went full auto on him. He sent it back several times to Winchester and of course they couldn't find anything wrong with it. I loaned him Nonte's book and told him to read the chapter on reloading gas guns. Went by a couple of weeks later to get the book back and asked if it had solved the problem. He opined it had. When I inquired about the 100 he told me he couldn't shoot it fast enough and had traded it for the bolt 270 in the corner behind me. He was the same guy who shot a 20 gauge Remington 1100 at skeet and I swear the hulls flew 20 feet from the gun when he shot.

[Bullwolf]

Instead of regular CCI large rifle primers, try using the CCI military style rifle primers.
No. 34 specifically, for 7.62x39 large rifle.


CCI® No. 34 and No. 41 MILITARY RIFLE PRIMERS

Military-style semi-auto rifles seldom have firing pin retraction springs. If care is not used in assembling ammunition, a “slam-fire” can occur before the bolt locks. The military arsenals accomplish this using different techniques and components—including different primer sensitivity specifications—from their commercial counterparts. CCI makes rifle primers for commercial sale that matches military sensitivity specs that reduce the chance of a slam-fire when other factors go out of control*. If you’re reloading for a military semi-auto, look to CCI Military primers.
*Effective slam-fire prevention requires more than special primers. Headspace, chamber condition, firing pin shape and protrusion, bolt velocity, cartridge case condition, and other factors can affect slam-fire potential.

Mil-spec sensitivity
Initiator mix optimized for ball/spherical propellants
Available in large (No.34) and small (No. 41) rifle
Use the same data as CCI Magnum primers
USAGE:
Military-style semi-automatic rifles


http://www.cci-ammunition.com/products/primers/primers.aspx?id=30









http://www.kygunco.com/prodimages/32549-DEFAULT-L.jpg

Make sure you seat the primers flush as well. Unexpected "slam fires" are not fun.


- Bullwolf

[milrifle]

Those would likely solve the problem. I've seen the small rifle ones for 5.56, but I don't recall seeing the large ones. I'll keep a look out and buy some when I see them. Meanwhile, I'm gonna try to work up a load for this thing, but I think I will limit the number of rounds in a magazine, at least until I feel like this was a fluke and not something that's gonna happen all the time.

When this happened, I had loaded 10 rounds of one load and 10 rounds of another load 1 grain higher to check for consistent cycling. The lower one (17 gr RL-7 under Lee C312-155) cycled most of the time, but had 2 failures to feed in 10 rounds. The double fire happened on the first shot of the 18 gr load, but it was the only time in those 20 rounds that it happened.

[Alexn20]

I would continue shooting it and see if it happens again. I am curious but I put my $$ on slam fire.

[justashooter]

Inertial firing pin design on the AK does not have a return spring. This kind of second fire with light strike can occur with thin commercial primers. MK was not thinking about this when he opted out on the return spring idea.

[milrifle]

I shot it a few more times (Read that "I lost a few more cases") last weekend. No more slam fires. I meant to pull an unfired chambered round and look at any primer dimples, but forgot. You can bet I'm careful where the thing is pointed when I chamber a round. I don't want any missing my backstop. It's nothing but woods behind my target, but I still like to keep 'em all on my own property.