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I cracked my s12 reciever....PICS!!!


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Hey guys so I'm looking for a little perspective about my IZ-108 and what the best course of action may be. It was converted here at the house, and a 12k style rear trunnion was welded in.

 

pic1.jpg

 

This trimming operation was never done because I didn't know about it and the bolt carrier was riding up the rear trunnion arms...usually powered by Winchester super x shells. I got lucky and the carrier really didn't get banged up all that bad as far as I can discern. Neither did the folding stock trunnion although it can clearly be seen where the harder carrier metal sheared off the most material, on the opposite side of the cracks, same side as the "pinch" in the carrier rail channels

 

pic2a.jpg

 

pic2b.jpg

 

pic2c.jpg

 

There is a slight "pinch" at the very end of the carrier where it rides the receiver rails on the serial number side. The worst can be seen at the flattened rearward most feature of the carrier

 

pic3a.jpg

 

pic3b.jpg

The receiver is cracked on the charging handle side where the trunnion arm would have been riveted in place, the old axis pin hols seemed to have provided a little pathway for the cracks to relieve themselves. There is also a crack in the safety keyhole.

 

pic4.jpg

 

The finer cracks are slightly hard to pick out so here is a bit of photo shopping to cover them all. There is also a slight dent in the ejector block as well as the bolt channel in the carrier.

 

pic5.jpg

 

 

pic6.jpg

 

pic2d.jpg

 

 

Thank goodness I was usually broke and didn't have the money to send hundreds of slugs downrange at a time. I estimate no more than 250 slugs have ever been fired through this firearm. When the cracks were discovered I quit shooting this gun for fear of making the cracks worse and its been collecting dust ever since. I havent posted in a long time so I figured "what the hell, lets see what some others think. I might also hear from a few professional smiths to determine if this thing can just be welded up." My goal was to have a 12k style sbs with a 10 inch barrel. Can the cracks be fused or is it better to count this saiga as a candidate for aow pistol conversion?

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Sorry for your damage but I guess it is a testimonial to the AK design it would operate at all.

 

If you have corrected what was causing the problem what would be the danger or effect of operating it with those hair line cracks in the receiver?

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Just my opinion but it could it have been the welding that left the metal in such a state to start cracking?

 

Exactly what I was thinking. Clearly, all the cracks are either originating at or converging to the weld. I would guess that the receiver was heated too much when it was being welded up.

Edited by elvis christ
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Just my opinion but it could it have been the welding that left the metal in such a state to start cracking?

 

Exactly what I was thinking. Clearly, all the cracks are either originating at or converging to the weld. I would guess that the receiver was heated too much when it was being welded up.

 

Yeah that's what I was concerned about, the receiver is really thin. This was all done with a MIG so the heat wasn't really localized and there was no heatsync on the receiver when the welding was taking place. I remember the magazine being more difficult to rock in after all the welding was done....everything is more than likely warped in some way but yeah it still went boom when I went click. That being said I am unsure about weather or not welding it any further would make it stronger or weaker lol. I'm sure some others will chime in to the discussion, but I appreciate your observations.

Edited by Azkamidaka
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Sorry for your damage but I guess it is a testimonial to the AK design it would operate at all.

 

If you have corrected what was causing the problem what would be the danger or effect of operating it with those hair line cracks in the receiver?

 

 

One of our experts here, Tony or Wil, may be able to fix you up.

 

Well rocinante there were never really any corrections made, that's why it doesn't get shot lol. The carrier pretty much made its own path through the rear trunnion and was slightly pinched in the process. I just don't want it to blow up in my hands while shooting high brass slugs. It is a pretty awesome design though your right and the chance it would blow up at all is infinitesimal but you know about safe and sorry and all that.

 

Patriot, I have full faith and confidence that either one of them could revive this twisted Russian. I just like to share a bit beforehand just to see what others minds have to add. Thanks for the replies guys.

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Just my opinion but it could it have been the welding that left the metal in such a state to start cracking?

 

The amorphous discoloration around the weld represents metal that has been annealed or partially annealed due to the extreme heat generated at the weld point.

 

If you closely watch the video above you will see that the AK receiver flexes as the carrier moves back and forth. When all of the metal in the receiver retains a factory temper - everything is flexing/stressing at the same rate. When there are a range of hardnesses (from very hard to dead soft to factory temper) within the same expanse of metal, the hard stuff resists, the factory temper flexes as designed, and the soft stuff in between expands and contracts at a different rate, eventually causing fatigue and failure.

 

Basically your receiver is cooked, and no longer safe. You could attempt to weld up the cracked areas, but the problem is compounded with every weld made.

 

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Just my opinion but it could it have been the welding that left the metal in such a state to start cracking?

 

The amorphous discoloration around the weld represents metal that has been annealed or partially annealed due to the extreme heat generated at the weld point.

 

If you closely watch the video above you will see that the AK receiver flexes as the carrier moves back and forth. When all of the metal in the receiver retains a factory temper - everything is flexing/stressing at the same rate. When there are a range of hardness (from very hard to dead soft to factory temper) within the same expanse of metal, the hard stuff resists, the factory temper flexes as designed, and the soft stuff in between expands and contracts at a different rate, eventually causing fatigue and failure.

 

 

Yes I see. Well that certainly adds sense to the reason the cracks appeared. With this in mind I am leaning towards making this shotgun a candidate for an AOW pistol.....I wonder if the folding stock trunnion could be salvaged if the old receiver would be destroyed anyway. I would still like to hold onto the parts to make my dream build the 12k 10'' sbs. Thanks very much for your input WaffenSchmied.

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Sorry for my typo in my first post. It was actually an attempt to change my statement into a question after the fact....to try and avoid confrontation with the "weld everything" fans here. I am not a fan of using welding to attach any part to the AK receiver....never have been. It's not just because I don't personally weld either. The AK was designed the way it is for a reason. Steel rivets are the way to go when attaching any trigger guards or trunnions, to the receiver.....IMO of course....

Now that being said....When certain very experienced gunsmiths like Tony, WIll, etc...weld a rear block to the back for a stock adapter, or even tig a TG on...they know exactly what they are dealing with, and take everything into account.

I personally prefer a riveted on TG (when I do one)...because that's how the AK was originally designed, and I'm fully equipped to do them that way. To each his own though.

 

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Wow that sucks man. Thanks for posting this up. I got this folding stock and am not real sure if I'm supposed to take material off of the rear trunnion. I'm riveting mine in so I won't have weld fatigue. I'm not even having the old FCG holes welded just because I didn't want to chance compromising the metal. I'll just use the plastic plugs. Do any of you know if the rear trunnion on mine needs material taken off? It's going on an S12 and yes I got the correct front latch (from Cobra).

Edited by jamesmadison
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Sorry for my typo in my first post. It was actually an attempt to change my statement into a question after the fact....to try and avoid confrontation with the "weld everything" fans here. I am not a fan of using welding to attach any part to the AK receiver....never have been. It's not just because I don't personally weld either. The AK was designed the way it is for a reason. Steel rivets are the way to go when attaching any trigger guards or trunnions, to the receiver.....IMO of course....

Now that being said....When certain very experienced gunsmiths like Tony, WIll, etc...weld a rear block to the back for a stock adapter, or even tig a TG on...they know exactly what they are dealing with, and take everything into account.

I personally prefer a riveted on TG (when I do one)...because that's how the AK was originally designed, and I'm fully equipped to do them that way. To each his own though.

 

 

To err is human Cobra. I hear ya though. I would've loved to use rivets as well. The reason for choosing to weld in the first place was that I had no means to compress rivets like yourself and others who are vested in the tools to do a proper job. I was attempting to save a few bucks here and there to put toward the retaining latch hardware holes to be machined by someone with pro grade tools, the ATF fees for sbsing, as well as the cost to cut the barrel down and get the gas tube shortened and new gas holes drilled. Thanks again.

Edited by Azkamidaka
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Wow that sucks man. Thanks for posting this up. I got this folding stock and am not real sure if I'm supposed to take material off of the rear trunnion. I'm riveting mine in so I won't have weld fatigue. I'm not even having the old FCG holes welded just because I didn't want to chance compromising the metal. I'll just use the plastic plugs. Do any of you know if the rear trunnion on mine needs material taken off? It's going on an S12 and yes I got the correct front latch (from Cobra).

 

I know!!! lol big time. But yeah man thats the EXACT same one I got from KVAR.......hopefully you can save your shotty from the fate of mine. EDIT TO ADD: Wait a minute that part says something about angles being slightly changed so perhaps its not the same. Be wary.

 

 

Good thing I bought a IZ-107 during the ATF shotgun study, but its hardly a candidate for a sbs when this 108 over here is looking like it needs to go to CGW, and beautiful things can be done with mid bbl comps on 24 inchers.

Edited by Azkamidaka
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Basically your receiver is cooked, and no longer safe. You could attempt to weld up the cracked areas, but the problem is compounded with every weld made.

In theory, could you strip the receiver, weld it up and then re-heat treat the whole receiver? Practically I suspect it's cheaper to buy a new gun, but would that produce a safe gun if you had someone who would do the work?

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If you ever do decide to sell your folding stock setup, I'd like to know. I ordered a S12 VER 30 from Red Dragun. If it ever makes it here, I'd like to add the folding stock to it. You can P.M. any time.

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Sorry for my typo in my first post. It was actually an attempt to change my statement into a question after the fact....to try and avoid confrontation with the "weld everything" fans here. I am not a fan of using welding to attach any part to the AK receiver....never have been. It's not just because I don't personally weld either. The AK was designed the way it is for a reason. Steel rivets are the way to go when attaching any trigger guards or trunnions, to the receiver.....IMO of course....

Now that being said....When certain very experienced gunsmiths like Tony, WIll, etc...weld a rear block to the back for a stock adapter, or even tig a TG on...they know exactly what they are dealing with, and take everything into account.

I personally prefer a riveted on TG (when I do one)...because that's how the AK was originally designed, and I'm fully equipped to do them that way. To each his own though.

 

 

To err is human Cobra. I hear ya though. I would've loved to use rivets as well. The reason for choosing to weld in the first place was that I had no means to compress rivets like yourself and others who are vested in the tools to do a proper job. I was attempting to save a few bucks here and there to put toward the retaining latch hardware holes to be machined by someone with pro grade tools, the ATF fees for sbsing, as well as the cost to cut the barrel down and get the gas tube shortened and new gas holes drilled. Thanks again.

 

 

Hey not trying to fault you, or your decision to weld bro. Just expressing my opinion on the matter while there is concrete proof here to back my reasoning. I've basically been told I'm full of shit before, for feeling the way I do about welding on these things. I won't speak for others who share my opinion (they don't like that...) but I'm not alone.

 

 

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Wow that sucks man. Thanks for posting this up. I got this folding stock and am not real sure if I'm supposed to take material off of the rear trunnion. I'm riveting mine in so I won't have weld fatigue. I'm not even having the old FCG holes welded just because I didn't want to chance compromising the metal. I'll just use the plastic plugs. Do any of you know if the rear trunnion on mine needs material taken off? It's going on an S12 and yes I got the correct front latch (from Cobra).

 

I know!!! lol big time. But yeah man thats the EXACT same one I got from KVAR.......hopefully you can save your shotty from the fate of mine. EDIT TO ADD: Wait a minute that part says something about angles being slightly changed so perhaps its not the same. Be wary.

 

 

Good thing I bought a IZ-107 during the ATF shotgun study, but its hardly a candidate for a sbs when this 108 over here is looking like it needs to go to CGW, and beautiful things can be done with mid bbl comps on 24 inchers.

 

The angle changes they are talking about are the angle of the stock. The old one has a 4.5 pin and trunnion the new one has a 5.5 trunnion and pin and puts the stock a little more inline with the receiver. The basic shape of both trunnions are the same so he would need the remove the material from it as shown in the first pic of this thread.

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The receiver is a different steel than the carrier & trunnions.

 

I'd weld up the receiver cracks with 4130, remove the front trunnion & redo the heat treating on the receiver just like you'd do a receiver flat that one was building a kit gun on.

 

Get a rivet tool & reinstall everything

 

Problem solved.

There's your project for the month.

 

Welding on guns isn't scary or dangerous if people know their metallurgic properties & how to mix metals taking into account the characteristics of each including expansion & contraction as the finished piece cools & how to properly heat treat. It takes a bit of research & a bit of skill

 

If they are unaware of correct procedure, then it is not a good idea to weld. There's an undeniable place for welding, silver solder brazing & riveting in gun smithing.

The right method in the right place with the right precautions before, during & after the procedure(s) make all the difference.

 

That being said, rear blocks IMHO really should be riveted.

The impact of the carrier on the rear block from a shotgun is really going to stress the joints.

Annealed steel is less likely to actually crack & more likely to deform than harder steel, but welding the rear block leaves no room for movement or shock absorption, thus cracks form & travel.

Rivets give a little much needed play in that area.

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Wow that sucks man. Thanks for posting this up. I got this folding stock and am not real sure if I'm supposed to take material off of the rear trunnion. I'm riveting mine in so I won't have weld fatigue. I'm not even having the old FCG holes welded just because I didn't want to chance compromising the metal. I'll just use the plastic plugs. Do any of you know if the rear trunnion on mine needs material taken off? It's going on an S12 and yes I got the correct front latch (from Cobra).

 

That's the same trunnion and stock I'm having installed on my SBS. If you look at the pictures, the "new generation" trunnion that comes with that set looks slightly different than other versions. Judging from the pictures and from looking at the trunnion in person before shipping everything off to be assembled, the area where material needs to be removed is already how it needs to be for the Saiga 12 right from the factory and the angle is slightly different.

 

I will post more in my SBS thread when my build is completed and returned to me.

 

Compare these 3 pictures to see the difference in trunnions:

 

http://www.k-var.com/shop/product.php?productid=17651

 

http://www.k-var.com/shop/product.php?productid=16847

 

http://www.k-var.com/shop/product.php?productid=17039

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You know, I thought it looked ok (my k-var folding stock trunnion), but jeez as everyone knows there are no hard and fast guidelines on building these beasts. A lot of it just seems to be make it up as you go!

Wow that sucks man. Thanks for posting this up. I got this folding stock and am not real sure if I'm supposed to take material off of the rear trunnion. I'm riveting mine in so I won't have weld fatigue. I'm not even having the old FCG holes welded just because I didn't want to chance compromising the metal. I'll just use the plastic plugs. Do any of you know if the rear trunnion on mine needs material taken off? It's going on an S12 and yes I got the correct front latch (from Cobra).

 

That's the same trunnion and stock I'm having installed on my SBS. If you look at the pictures, the "new generation" trunnion that comes with that set looks slightly different than other versions. Judging from the pictures and from looking at the trunnion in person before shipping everything off to be assembled, the area where material needs to be removed is already how it needs to be for the Saiga 12 right from the factory and the angle is slightly different.

 

I will post more in my SBS thread when my build is completed and returned to me.

 

Compare these 3 pictures to see the difference in trunnions:

 

http://www.k-var.com...productid=17651

 

http://www.k-var.com...productid=16847

 

http://www.k-var.com...productid=17039

Edited by jamesmadison
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I call dibs on your top cover.. Just kidding really I would weld that thing back together and see what happens and do alot of shooting from the hip for a while...

 

You're saying that you don't want to shoot something in that condition close to your face but you'll put it near your balls instead? :lolol: :lolol:

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I call dibs on your top cover.. Just kidding really I would weld that thing back together and see what happens and do alot of shooting from the hip for a while...

 

You're saying that you don't want to shoot something in that condition close to your face but you'll put it near your balls instead? :lolol: :lolol:

 

 

what can I say but I am pretty!!LOL

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I don't have much to add here except that the dent in the ejector block is from letting the unconverted hammer to fall forward without the bolt in place. Slams that little spot pretty hard, know from experience and mine looks identical. My converted hammer doesn't go that far forward.

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Just read this thread today and it looks like.. Mike, (Waffenschmied), has already explained the problem, better than I could have.

 

Welding on the receiver may not always result in stress fractures, (depends on the skill of the welder), like those pictured above, but it vastly increases the chances of such a problem developing.

 

ymmv.

Edited by post-apocalyptic
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