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Not all stoppers are created equal

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The "stopper" (official part name) is what you select "1" or "2" to adjust the gas flow that goes to the piston.


Setting "1" is when you use more powerful rounds -such as slugs or buck shot.

Setting "2" is when you use lighter rounds -such as game, skeet, or bird shot.


Sometimes you can get away with the "lighter" loads on the setting "1"....sometimes you cannot.



I own two S12 guns. One is a standard stock, the other is a Tromix.

I noted after various testing between the two that some "light" rounds have hard times cycling when on setting "2" (even after "break in" period).

So, I compared a couple things.


Granted, I just came off the range and haven't cleaned it as yet. I wanted to share this with people that might be troubleshooting cycling issues.


First, in all the pics keep this in mind: They are both the SAME model.



OK... as you can see from below, there are 3 differences/attibutes:

LEFT Stopper...

1) The "pin" on top is taller.

2) There is NO flat spot for the "magnum" rounds (for setting "1"). Please note that it still cycles reliably since theres PLENTY of gas.

3) The "ramp" for setting "2" is shorter and not as long a cut. This does cause an issue with cycling on occasion -even with light rounds. Especially if "dirty".


RIGHT Stopper...

1) The "pin" is shorter. This apparently is supposed to prevent the piston from moving over the top of the gas ports directly (from bolt movement forward).

EITHER way, the overall length of the stopper itself after you thread it on there, the main body goes past the gas ports from the barrel. Shouldn't be any factor really.

2) The is a small flat spot for the "magnum" rounds (setting "1"). Absolutely NO issues with powerful rounds of course...and some heavy game rounds work as well).

3) The "ramp" is much more apparent. Between the two, I think this longer ramp (and slight angle) really improves the lighter loads to cycle (even dirty).



post-5106-1175764574_thumb.jpg post-5106-1175764601_thumb.jpg


post-5106-1175764624_thumb.jpg post-5106-1175764636_thumb.jpg





Overall, I think I like the small "flat" spot for the magnums. It doesnt hit any harder -but definately aids in the "game" loads from working better (bird still =no way). I will probably grind a similar one on the left so it performs better with "medium" shot loads like the other one does. Hmm... I've had "1" FTE on setting one, and it was on the one without the flat spot. I thought it was probably from being gummed up...but now, not so sure after comparing.

So yeah, I think it needs to be there. Its NOT much...just a very small clearance really. But it serves a purpose obviously.


Next, the pin on top... I see no difference in performance that could be related to this pin. No plans to gind that at all. If anything, I wonder if the "short" one was made too short. As stated earlier, I see no issues with it really. Its PROBABLY there just so IF the piston hits, it will be dead center and not damage the threads. Hmmm... perhaps shorter is better (if piston doesnt hit the shorter one, there's less chance for "stuck" or "jammed" threads).... no serious problems detected for that though at all. No thread damage as you can see.


Finally, the ramp. I think that the longer ramp on the right stopper is the proper angle (please note the depth on the top towards center as well)...

The cycle response I get from that stopper when placed in the other shotgun improved its performance for lighter loads (virtually zero Fail to Ejects with that one). I'll probably grind out the one on the left a little just for piece of mind.


So yes....your cycle performance is very much tied to this single part. All my opinion though. After comparing and swapping them out, I think its very true though.



Anyway...for those who only have a single S12, I thought I'd share so it might give you an idea if you're trying to determine "which round" does the best...or "which setting" or whatever. Hope it helps people out there.


AND REMEMBER... above all else: You can grind it off, but you can't really put it back~! "Adjust" at your own peril. This is just reference and opinion. I'm no gunsmith, and so no, I won't fix things if you go "dremmel happy".



Zombies beware: Quality Control is improving.



PS...ok, now I'm cleaning them for a bit. I know. I know.

Edited by whatmanual
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Hmmmm. Seems to be lots of variation.

The gas plug from my S-12 looks like the one you have on the right except that the "pin" is almost ground flat with the face of the plug & it has no flat spot on the magnum side, so that side looks like the picture on the left.


Cycling has always been flawless & I leave it in position 1 at all times. Even when shooting the cheap, light loads from waly-mart.

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Do you know if Tony does any work on these (in an effort to attain reliability?). What version of the Saiga did Tromix make for you? There are different patterns of gas ports in the base gun. And if you have your bbl shortened, it's possible that an additional gas port needed to be added. That in turn could require a different plug?


Do you keep them straight? (i.e., do you know which one went on which shotgun originally?


I'm going to have to pull two out to take a look now.

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The one on the Left in all the pix is from the Tromix (please note the extra cleaning required -hehehe...was a fun day)

The one on the Right is from my original S12



Both are identical 109 series base model (with 19" barrel and BHO etc etc). Tromix does outstanding work and isnt the issue. My point was that my original S12 apparently has a different slope for the "2" setting, and a flat spot for the "1" setting.



In my opinion, the one on the right peforms better (stock S12 109). The on the left (stock S12 109 then converted by Tromix) performs mostly well -but has some issues with lighter loads. I will say it seems to thread on and off smoother as well. Furthermore, the Shark Break, craftsmanship, magwell, and overall "feel" of this one more than make up for the "manufacturing" difference.


As a side note: I placed that stopper on the "right" into the Tromix to test out the theory. It made a perfect weapon now flawless in all action. I couldn't get it to FTE at all (double taps and rapid firing). So.... I'll be adjusting that other stopper to match now and then place it back where it truly belongs.



As I've been told (and said elsewhere on the forums)...

Its like with the mags sometimes fitting in one gun but stick in another. That is because (in theory) the "worker" simply takes the mag on hand, taps the cigarette, checks the mag fit, and grinds around the edges a bit so "that" mag fits nice and snug...taps the cigarette again, and moves on to the next.

~this says nothing of course what YOU will find when you place different mags in there. Might fit loose, just right, or simply no way.


In short, I believe this to be the case with other areas like the stopper. In my opinion, clearly a manufacturing quality control issue -not a conversion issue.




Edited by whatmanual
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The left and right are accurate in the picture.


Right = My 1st S12 that is unconverted I bought about a month before at a gun show (new).

Left = My 2nd S12 is an original S12 (new)...bought from and then converted to a Tromix probably a month later. Gotta love one stop shopping :)


I know this is accurate based on the black finish (and numbers) between the two. My original one weared off rather easy and the Tromix finish is still nice color to it. No doubts.



That would essentially mean that my original (unconverted) S12 "came" that way, and that the Tromix one came that way as well prior to its conversion.

My question, and point, was that if they "both" came from the same factory........are they using all the same specs?


Heck..perhaps I got a stopper from some other series fitted to my original S12? Or maybe they fitted a more shallow one to the S12 they shipped Tony?

Several possibilities. Either way, its not


I just thought to bring this to light.



PS: for no confusion, I'm a Tromix customer for life. This thread is about the PART specs back to the MFG plant -not the conversion results (which I'm more than happy to say my Tromix is my weapon of choice -hands down and without question).

Edited by whatmanual
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Same annotation as my above pictures...


Left = Tromix

Right = my stock S12.



Clearly the stopper from Tromix has a better finish (as I said) and I also noted that it has "ridges" on the ring there....where as, the other is flat flat.

This supports my theory that they are 2 different types of stoppers (revisions) coming from perhaps different plants.









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Serial numbers practically match as well too ....hmmm


Less than a 400 number difference~!


(stock) H064212xx

(Tromix) H064216xx


("xx" for my protection).




Must've came from same place -probably the same boat :)

....so only quality control, part revision change, or "substitute" part makes sense.




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SN is H014148xx, much earlier than yours. import date is 2002, if I recall correctly. the one I had for a week before this one and sold, was a kalashnakov USA 00 #. I will ask my sister what her 410 and 7.62 KUSA SNs are the next time i talk to her.


we need the system of labeling posted here.


I also notice a marking on the left side of the reciever, immediately muzzle forward of the scope/sight rail, underneath the marking on my gun, of an oval, surrounding two oppposite cyrillic "E", with vertical arrow mark centered between them, whichhas an apparant different tooling mark of "01" immediately underneath this marking of, my gun's make year,im guessing.


to the immediate left of that, is an "MX03" stamping, (above THAT stamp, is a "PCT" marking, in graphic form, P enclosed by a C, ((you will know it when you see it)) with the "T" outside of the "C" surrounding mark) with an apparant same tool/pressure as the itzmash markings. the "X" has a vertical line in it, as per cyrillic. I am guessing without looking first, that this is my gun's model number.


I need to go buy my own digital cam, I guess.


oh, I also am under the impression, that the SN thing is USA related, not done in the factory. they label them all in one shipment. adding to the confusion. fortunately it is a 12 gauge AKM, but UNfortunately, the output of soviet arms plants is a guarded secret. IT MAY NEVER be informed correctly.


give me dater. Ill figure it out. I am extremely interested in this topic.

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the "06" on yours, is on mine, 01. maybe revision number? PROBABLY the year it was MADE, though. are yours both the same marking? my "01" is marked to the RIGHT of where yours are, but still under the emblem. not a lot, all the way, like it is justified from right to left, like a muslim made mine or something.


Ive always been curious as to what revisions worked best. my s12 when I got it and over the years, seems to be very tolerant and is almost unique, if I could even say that. it eats all shells on #1 setting and laughs at all of us when we try to "trick" it.


manuf. pattern is changed on yours. all marks are aligned slightly different, outside of manu. spec, than yours are. right weld dimple (NOT THE DIMPLES FOR RECIEVERS FOR YOU SEARCHING PEOPLE) is well right of your pic. itzmash log is well right of yours, as well. are both of yours the same?



also. I have F(1,0) directly underneath the chamber marking, directly under the 12x76 marking, same tooling marking. mine reads "EAA CORP COCOA, FL" on the back part of the reciever, on right side.


could someone with a kalashankov USA model saiga 12 post thier information here, please. or several of you.


this needs sorting.


that number under the one mark sounds like a revision number to me, but more likely, the actual date of manufacture. need more dater. daterdatterdaterdatterdaterdatterdaterdatterdaterdatterdaterdatterdaterdatterdat

erdatter input. :)

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Doh, my new Saiga looks like it has the same one as yours on the left. I didn't pull it out, I am just juding by the ridges I see on the outside, and that the settings are labelled in white numbers.


Oh check this out, my serial is pretty close to yours:




The certificate I got with my gun is dated 7-8-2006


Here's the best I can do to get a photo of it while it's in place, so you can see how it has ridges like the "bad" one you show. Man now I wish I can replace this with one like the one you have on the right, even though I haven't fired it yet to see how it cycles.


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I wouldn't exactly call it "bad" .... the Saiga will still be picky about types of ammo. Its just that I feel the stopper gives a large contribution to that.

With the ridge stopper (shorter ramp, and no flat spot), it will still cycle slugs/buck on the "1" setting with some good reliability. Its when you start shooting "shot" type rounds it becomes questionable. This is due to the points I presented above (in my opinion...but Im no gunsmith).


Seeing the pic for the .410 stopper....makes me wonder. I wonder if those type of parts are universal regardless to the gauge. If so, then its pretty much "grab from the bucket" and assemble (regardless of which "shop" made them and shipped them to the assembly plant). In manufacturing, its not uncommon for components to be made in several locations.



Keep in mind, it was also said that one option is to simply back it out 1 extra turn instead of being flush to the block. That would help compensate for lack of ramp distance.

I personally would not advise anyone to simply grind away at something without THOROUGHLY testing it (and breaking it in very well) with several types of ammo and settings. Even then, hope they are real good with a dremmel for smoothing it out etc.

Again, Im not making this thread to fill anyone with dread.... more like: factors to consider in troubleshooting cycle issues.




Edited by whatmanual
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Samuel Colt was the person to start manufacturing "machinery" with standard interchangeable parts. Until then everything was custom. His six shooter changed the world!


I have toyed with naming my 410 but nothing has stuck yet. I have changed her configuration a couple of times and maybe that has something to do with it. The first time I pick up my S-12 "Hello Ivan" just came to my mind (or whats left of it!) :up:

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Samuel Colt was the person to start manufacturing "machinery" with standard interchangeable parts. Until then everything was custom. His six shooter changed the world!


I have toyed with naming my 410 but nothing has stuck yet. I have changed her configuration a couple of times and maybe that has something to do with it. The first time I pick up my S-12 "Hello Ivan" just came to my mind (or whats left of it!) :up:




If I remember my high school history, Eli Whitney started the principle of interchangeable parts a few years before Colt.

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