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Hi, New guy here, I signed up when I picked up a Saiga 12 and decided to SBS it my self. Typical of my character I am willing to take the harder road in order to get better results and this sight has helped me through the process.


Here is the point I am at. I moved the gas block back 2.250" welded up the old gas ports re drilled 4 new ports at .073 each.

I have the gas block and a Tromix short gas tube and bolt carrier extension installed. I still have the original puck in it and the bolt carrier is making contact with the puck.


My question is: How much end play should I have between the extension and the puck and what is the best way to get what I need.


I am waiting on my form 1 to come back, I have the barrel turned down so that I can cut to 12" and thread once it is ok'd but for now I have it cut and a flash hider welded on to get me over 18" until my form 1 happens


In the pic you can see the distance that the regulator is sticking out when the puck starts to make contact with the bolt.

Thanks in advance


Also if you click on one of the pics you can cycle through my process and critique it. This is my first attempt and I welcome any constructive criticism.





Edited by AllenM
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The tolerance between the end of the piston rod (what you are calling a bolt carrier extension), the puck  and the gas adjuster plug is forgiving.  Obviously there must be clearance so that when the bolt is fully forward, the puck is not hitting the gas adjuster plug .     1) Put the bolt into battery   (farthest forward position of the piston rod),  2)  push the puck against the piston  rod (farthest rearward position of the puck).  3) now measure the distance from the front face of the puck to the end of the gas block.    You should have between about 0.800" and  0.900"  with a stock gas puck. 

  I would suggest that you get a different gas plug.   Various good options out there-  see various threads in this forum.  


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I would shoot for about .050" of gas puck play when the plug is screwed in all the way. That gives you some leeway for fouling buildup and dimensional changes due to temperature changes during firing without losing much cycling power.


Keep in mind some pucks are longer than others, so measure this with the longest puck you plan on using.

Edited by JonWienke
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The Tromix bolt carrier extension is purposely made a bit long for the gas tube, so you can fit it to your gun.


Tony Rumore



I was wondering if I should turn it down or clearance the inside of the plug. Once I get the new plug, if it still needs it.


That is the answer I was looking for. Thanks

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  • 1 month later...

Thanks a bunch to the info I found on this forum I now have my Saiga 12 ready to SBS  once my stamp comes through. It has been submitted just over 3 months now, so any day I should be getting it back.

I wanted to share some pictures. This is just a gloss over of the work involved but I wanted to post.


This took so long, one because I am waiting on a stamp and, Two because I work 2 jobs.


So here is a pictorial of my build:


When I bought it used it had already been converted with a bolt hold open installed




I wanted to go 12" and base on info here I decided the right thing to do was move the gas block back, However in hindsight i realize now I really did not have to pull the barrel from the trunnion....but I did. While I had the barrel out I turned it down to thread after the 12" cut.


Made a barrel pusher 




welded up old gas ports and gas block retainer groove and turned barrel






profiled and polished feed ramp




Located and drilled 4 new .073 gas ports  2.25" back from original






Replaced bolt carrier with Tromix short extension




Removed old gas tube




installed Tromix Short tube. As you can see in this pic I did cut the barrel to 16.25 and slip fit and welded my old flash hider since I will not be using it when I am done.




Fit a Chaos rail system to the new handguard location  






removed rear tang and added Tromix butt plate and stock










SBS ready and ready to test fire. 

Took it to the range and it ran like a champ on everything I had with me.


I did some bolt reprofiling and polishing but didn't take any pics.






Once it passed function test I took it back apart and refinished it with Cerakote FDE








I have this Tromix brake for after it is cut











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