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sourceofuncertainty

Please help diagnose a chronic FTE problem

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Hi all,

 

A quick "back story" and then on to my plea for help. A while back I purchased a very low mileage stock S12 with the intent of converting it at some point. About a month ago I came across a converted S12 for sale locally. It had basically all the features I wanted to put onto mine, so I purchased it figuring it'd be a short cut to the Saiga I wanted. I planned to sell the stock Saiga but figured I'd make sure the conversion was running nicely first.

 

Well, 3 trips to the range later, I'm frustrated as hell. My bone stock Saiga 12 will cycle everything I toss at it with near-perfect reliability. But this converted Saiga is running a nearly 100% FTE rate. Yes, almost every shot FTEs. It gets stuck in the chamber on the way out, like it's short cycling on every round. The only exception seems to be really strong loads like slugs and buckshot. The gas setting doesn't seem to make a difference.

 

After my last frustrating trip to the range I took it apart and tried most of the tips I could dig up here on the forum. I gave the gas system a very thorough scrub, ran wire through the gas holes to clear them out, and gave the thing a thorough clean & lube.

 

Took it back to the range this morning with 5 or 6 different types of shells to try, and again no dice. The unconverted Saiga runs like a top with just about everything, but the conversion still FTEs almost every time, with all the various loads I tried. Both guns make the telltale piston "clunk" sound when clean, but I notice that after running 40 or 50 rounds through the unconverted Saiga, the clunk goes away - yet the gun still functions reliably.

 

One of the few clues I have - and this may just be a red herring and not a clue at all - is that the conversion seems to get stuck trying to load Winchester AA super sport sporting clay loads. On two different range trips I encountered a problem where upon insertion of a magazine it would try to strip & feed the top round but get stuck on the way home, leaving about 1/2"-3/4" of the shell still exposed in the breech. Once it was in this position the bolt was basically frozen in place, and I had to field strip it and do a lot of mucking about to get the bolt to move again.

 

It seems likely this isn't a mag issue - I'm using AGP 10-rounders; as I mentioned before the same mags run great in the unconverted S12.

 

Can anyone suggest next steps for troubleshooting? This is getting really annoying.

 

The conversion setup is as follows: G2 trigger group, K-var stock, welded on Tromix shark brake, and an FSE buttpad.

 

Any help or suggestions would be greatly appreciated!

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Is the chamber rough / fouled? Is this a cut down with the barrell shortened but the gas ports in the barrell stock, and not opened up to work the action with the reduced pulse from the shortened barrell?

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Is the chamber rough / fouled? Is this a cut down with the barrell shortened but the gas ports in the barrell stock, and not opened up to work the action with the reduced pulse from the shortened barrell?

 

Chamber looks fine to me. Good question on the cut down, though. It never even dawned on me that might be a factor, though I have had my suspicions about the muzzle brake possibly taking too much gas out of the gas system.

 

I'll take apart both Saigas and compare the gas ports side by side and will post the result...

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I know this is like a retard suggestion, but do you have the gas setting on the gun right?

 

Sometimes we can get absent minded.

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I know this is like a retard suggestion, but do you have the gas setting on the gun right?

 

Sometimes we can get absent minded.

 

I make more than my fair share of mistakes like that - but in this case it doesn't seem to be a factor. I triple-checked the gas settings, and even tried screwing it in all the way, then firing with the plug set on each setting, backing out one notch at a time... just in case it was marked wrong or something. Seemed to be about the same behavior regardless of the setting.

 

I checked the gas ports just now, and the two guns are identical - both have the three small ports.

 

Oddly enough, the piston in my stock saiga was -really- stuck in there hard... yet it continued to cycle perfectly at the range today. That's got nothing to do with the problem I'm trying to diagnose, just a commentary on Saiga's ruggedness.

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IIRC Tony posted a side by side pic of "new" pistons vs "old" pistons. IE the angle was different and the newer one wasn't getting enough gas. Check yours side by side and see if they are the same? Are these parts swapable between guns (that goes out to somebody who knows more Saiga-Fu than me)

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Is there a Buffer installed in the converted gun?... Hard Plastic pad inside reciever at the rear that cushions the bolts recoil,if so take it out and try again.Put a dab of lube on the rails and top of hammer when cocked.Have you tried any heavier buckshot loads?

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The main culprit seems to be when bbl's are cut back and gas ports aren't opened up. I'm doubting that the brake is bleeding gas off, but it doesn't count toward bbl length. (it counts towards legally, but doesn't hold the pressure wave).

 

Other ideas.

 

You might consider swapping out the bolt, and the springs between the two (make sure you can keep them straight, maybe make a small scratch?)

 

But my guess would be that the conversion has left the hammer/underside of the bolt connection too rough. Could you figure a way to measure how much pressure it takes to cylcle the two shotties? (possibly push the bolt handle against a scale to cycle it?) If not, can you tell a difference in hand cycling? Even if it's not the solution, it won't hurt to polish up those surfaces, you might even need to grind the hammer contact area down.

 

Hmmm, the only other thing that comes to mind, is the different handling of the two shotties. I doubt that this is the answer, but you might consider shooting the gun held against a tree to take the human factor out of the equation.

 

If you bought the shotty recently, and it was sold as a functioning gun, I'd consider demanding a refund, as it seems like someone tried a conversion, got it wrong and dumped it on the net. Otherwise, you have a bit of tweaking to get to a reliable gun.

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IIRC Tony posted a side by side pic of "new" pistons vs "old" pistons. IE the angle was different and the newer one wasn't getting enough gas. Check yours side by side and see if they are the same? Are these parts swapable between guns (that goes out to somebody who knows more Saiga-Fu than me)

 

I'd start with measuring the barrel length. There were a LOT of early conversions that folks cut down the barrels and did nothing to expand the gas holes to compensate for it. I'll bet nearly all of them have now been opened up at some point. I tried every trick in the book prior to nocking my gas block off and opening up the ports, and nothing worked until I bit the bullet and knocked it off. There should be a way you could get a small tool in there to measure the diameter and # of holes you have before just removing it, but this is beyond my smithing abilities and tools.

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Had the same problem on a buddy's conversion. The problem with his was in the triggergroup. I have always used the adjustable trigger group from Brownells and it dropped in with no alteration. My friend ordered the tapco and found that the hammer needed a little tweaking. He tried and it finctioned fine hand cycleing on the bench but jammed up at the range. I took the hammer out and gave it a little dremmel work and it works fine now.

Who did this conversion and what parts did they use?

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The pistons sure look the same to me. See attached pic.

 

The gas ports look the same to me too.

 

I'll try cycling them side by side to see if there's any noticeable difference in friction.

 

madmilo, where did you find the Tapcos needed dremeling? I'm guessing the hammer "face"? (not sure what the right terms is for that).

 

To answer some of the other questions:

 

- No buffers installed in either gun.

- The conversion has a Tapco FCG, It looks like a standard single-hook G2 but without removing it I'm not 100% sure. I do have a couple of spare G2s around and a Red Star so I suppose I could always put in a different trigger group and see what happens.

- I did lube the rails pretty thoroughly on this last attempt, using Brownell's action lube. Usually I just use break-free but figured it might need a little extra help on the rails. Didn't seem to make any difference.

- I didn't try any heavy loads in the converted S12 today, though on the last trip to the range I used some buckshot and slugs. It cycled those better than the light loads, though my recollection is that it still wasn't 100%.

post-5437-1182740898_thumb.jpg

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I'm starting to think it's the trigger group.

 

Looking at the two guns side by side, I see that in the cocked position, the G2 hammer comes up significantly higher than the stock hammer. That's probably enough right there to cause the additional resistance to the bolt when it's moving rearward. Though why the previous owner wouldn't have addressed that is beyond me. He was sophisticated enough to parkerize the gun and weld a Krebs sight on the thing... how hard could it be to dremel the hammer?

 

I've also just noticed that in comparing the two bolts side by side, there is a -lot- more play in terms of the "wiggle" between the bolt and bolt head in the converted gun. I have no idea how much play is acceptable, or if that's even a possible source of problems. But it makes me wonder if there aren't other problems here...

 

Can one purchase a replacement bolt for the S12 if that turns out to be a problem?

Edited by sourceofuncertainty

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I'm starting to think it's the trigger group.

 

Looking at the two guns side by side, I see that in the cocked position, the G2 hammer comes up significantly higher than the stock hammer. That's probably enough right there to cause the additional resistance to the bolt when it's moving rearward. Though why the previous owner wouldn't have addressed that is beyond me. He was sophisticated enough to parkerize the gun and weld a Krebs sight on the thing... how hard could it be to dremel the hammer?

 

I've also just noticed that in comparing the two bolts side by side, there is a -lot- more play in terms of the "wiggle" between the bolt and bolt head in the converted gun. I have no idea how much play is acceptable, or if that's even a possible source of problems. But it makes me wonder if there aren't other problems here...

 

Can one purchase a replacement bolt for the S12 if that turns out to be a problem?

 

I dont think its the bolt.G2's hammers are notorious for rubbing against the bolt,thats why i mentioned to put a little lube on the hammer when cocked.Likely as stated above the hammer (face) will need polished or even grinded down a bit.Ive had some that just needed a dab of grease and others 1/8" grinded off.Im guessing the problems that and light loads.

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With the bolt closed, drop a dowel or small tape measure down the barrel. How long is it to the tip of the brake?

 

18 7/8" with the bolt closed, to the very tip of the shark brake.

 

I noticed something interesting about the geometry of the hammer just now. I'm going to photograph it a little later...

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Ok, through the magic of macro photography, here are two pics of something I just noticed.

 

With the bolt installed but the spring taken out, if you move the bolt rearward until it -just- contacts the cocked hammer, you see two very different geometries between the two guns (pics attached).

 

The stock Saiga has a fairly modest rise in the angle of the hammer, and a fairly smooth transition between the bolt not touching the hammer at all, and resting on top of it.

 

On the conversion, the rise is much steeper, and the transition much more abrupt.

 

Do y'all agree that we may be on to something here? Or is this not relevant... It makes sense to me that weaker loads would encounter too much resistance when the bolt moved back. Stronger loads would be able to "overpower" the steeper hammer geometry.

 

If this is true then dremeling the hammer should solve the problem. The only question is - how much material to remove, and in what shape?

post-5437-1182803870_thumb.jpg

post-5437-1182803886_thumb.jpg

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That is normal for the G2,thats where the problems originate.You can take a quite a bit off as long as your grinding it flat to where it hits the bolt/firing pin.Before you go grinding, first just polish the hammer face real good using a Dremil and Flitz or Semi Chrome then add a dab of grease...fire a mag full of heavier rounds..polish/grind as needed.The gun may need broken in so shoot up some rounds /hand cycle a shit load of times before trying the light loads again.

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Take the new one Tapco hammer to a grinder and make it have the same exact profile as the Russian one you can smooth some of the edges but that would be your best bet.

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Problem solved. Your FTEs have absolutely nothing to do with the FCG. Your gun was probably originally 22" from the bolt face to the end of the muzzle. Those guns come with only three gas ports, not four like the 19"ers. Whoever did the conversion probably cut the barrel back too short for it to cycle light loads without enlarging the ports, or adding one more like they should have.

I measured my 19" factory gun and it's exactly 21" from the bolt face to the tip of the prongs on the Shark brake. That means your actual barrel is only about 17", maybe one of the first S-12s on the shipment to the newer importer RAAC. There is nothing you can do except knock or press off the gas block and enlarge the ports or add a fourth one.

 

What you are seeing on the hammer face is common. You could put the original Saiga hammer back in and it still would not cycle right.

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Problem solved. Your FTEs have absolutely nothing to do with the FCG. Your gun was probably originally 22" from the bolt face to the end of the muzzle. Those guns come with only three gas ports, not four like the 19"ers. Whoever did the conversion probably cut the barrel back too short for it to cycle light loads without enlarging the ports, or adding one more like they should have.

I measured my 19" factory gun and it's exactly 21" from the bolt face to the tip of the prongs on the Shark brake. That means your actual barrel is only about 17", maybe one of the first S-12s on the shipment to the newer importer RAAC. There is nothing you can do except knock or press off the gas block and enlarge the ports or add a fourth one.

 

Okay, now I'm confused. My stock Saiga is one of those 17" models with the welded-on choke. It's got the exact same gas port configuration as the conversion - 3 holes. It functions great. It measures about 18 1/4" from closed bolt to the tip of the choke.

 

I assume you're not saying that all S12s need the 4th port? And if that's not what you mean, then which piece of information is indicating that the conversion needs the port added/opened up?

 

ETA: I heard back from the seller. Apparently it was a 21" gun to begin with. Still, the 17" stock model with 0,0 choke only has 3 ports...

Edited by sourceofuncertainty

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Problem solved. Your FTEs have absolutely nothing to do with the FCG. Your gun was probably originally 22" from the bolt face to the end of the muzzle. Those guns come with only three gas ports, not four like the 19"ers. Whoever did the conversion probably cut the barrel back too short for it to cycle light loads without enlarging the ports, or adding one more like they should have.

I measured my 19" factory gun and it's exactly 21" from the bolt face to the tip of the prongs on the Shark brake. That means your actual barrel is only about 17", maybe one of the first S-12s on the shipment to the newer importer RAAC. There is nothing you can do except knock or press off the gas block and enlarge the ports or add a fourth one.

 

Okay, now I'm confused. My stock Saiga is one of those 17" models with the welded-on choke. It's got the exact same gas port configuration as the conversion - 3 holes. It functions great. It measures about 18 1/4" from closed bolt to the tip of the choke.

 

I assume you're not saying that all S12s need the 4th port? And if that's not what you mean, then which piece of information is indicating that the conversion needs the port added/opened up?

 

ETA: I heard back from the seller. Apparently it was a 21" gun to begin with. Still, the 17" stock model with 0,0 choke only has 3 ports...

http://www.powercustom.com/ is where you will find the trigger I was talking about. They no longer advertise the SAR which just dropped in but the regular AK trigger group will still work. You will have to dremel a little off of the sear hook that sticks up when installed. Takes about 5 minutes. This trigger is a little expensive but is fully adjustable. You can take all of the creep out of the trigger if you want to and lighten the pull. They sell the hammer seperately but it will not work with the G2, I tried that already. Be careful filing your hammer with a grinder. The heat build up softens the metal and the hammer will dent and change shape. If you go that route, use a slow dremmel or a hand file. It is a lot slower but you will be able to catch yourself if you start to screw it up using the slower method.

Don't count Cobra out on this though. The shorter barrel works better with larger gas ports so you may be able to handle your problem with labor instead of buying more parts.

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I'm with Cobra on this one (we are guessing over the net tho). Likely fix will involve opening those ports if they haven't been already. Can you see if they were enlarged in the conversion?

 

Grinding the hammer won't hurt (unless you fall asleep at the "wheel" :) ) It will likely help, especially polishing the surfaces that ride against each other. This may get you near 100%, but my guess is you really want to open up the ports. I mention this because you are going to be tempted to do the easy fix first, before changing the ports.

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The S-12 is a very inconsistant shotgun depending on several different things. The 19"er I'm referring to is MINE. It's a 2000 model EAA import. Your's was made to cycle rounds thru a 22" barrel with a fixed full choke if I'm not mistaken. The ports were not designed to function efficiently if the barrel was chopped off.

 

Case in point...I just bought a 24" bbl S-12 a couple weeks ago. Last week I was shooting the cheapest crappiest winchester wallyworld specials thru her rapidfire with no prob using brand new AGP 10 rdrs and the fiver that came with it. No jams, no FTFs, no FTEs nothing but good reliability. Then I cut the barrel back to 18 and a C hair and tried the same exact ammo thru the same mags. Guess what?....

 

And yours is shorter than that. ;)

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Is there a tuitorial or link here at the forum on how to open up the gas ports? I know of somebody else whos S-12 will not cycle the light stuff at all. Heavy loads will work though and he was asking me how can the gas ports be opend up. I dont know. Can anybody explain the process? Looking at the tiny holes in Ivan's gas tube makes me think it is not an easy job. :unsure:

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There is another option, put some kind of choke on it, I bet that the additional resistance of a choke even IC will force the gun to work, that is what Tom did with his famous automatic Saiga to get it to fire light loads. As far as I remember he never he did not mess with the gas ports although I could be wrong.

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Grinding the hammer won't hurt (unless you fall asleep at the "wheel" :) ) It will likely help, especially polishing the surfaces that ride against each other. This may get you near 100%, but my guess is you really want to open up the ports. I mention this because you are going to be tempted to do the easy fix first, before changing the ports.

 

Yeah, I sure would prefer not to remove the gas block (or whatever the right term is for it on an S12). I'm going to try grinding & polishing the hammer first. Worst case, I ruin a Tapco hammer and don't solve the problem. If that doesn't work I'll either go the gas port route, or just sell the damn thing to someone with more spare time than me & start over from scratch.

 

I certainly appreciate all the feedback, guys.

 

Now, who here has removed the gas block, and what all is involved?

 

Madmilo, it looks like you're talking about the Red Star adjustable trigger group. I happen to have two of 'em laying around. I was under the impression that they don't fit Saigas, but maybe what you're referring to is a different model.

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There is another option, put some kind of choke on it, I bet that the additional resistance of a choke even IC will force the gun to work, that is what Tom did with his famous automatic Saiga to get it to fire light loads. As far as I remember he never he did not mess with the gas ports although I could be wrong.

 

John is right about the choke. I chopped my Saiga-12 barrel from 22 inch to 19 inch and left it cylinder bore for a short while. I immediately had failure to load or failure to feed one out of 6-12 rounds depending on ammo. This was partially cured when I added a Remchoke and ground and polished the G-2 hammer and bolt assembly. Pull the bolt back and slowly ride it forward. If it stops on a part of the fire control group you will be losing reliability. Most conversions are done with shortening the barrel and adding U.S. triggers and hammers (ironically, the American parts often contribute to the unreliability).

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