what is the optimum hole size for the gas holes?

[Salt1219 176]

what is the optimum hole size for the gas holes? I have 3 and they are roughly 1/16 in size, my gun is seriously under gassed right now.

 

I will try several other things before i resort to drilling up the holes, I just wanted to know if they are smaller than normal.

[k_ritala 2]

.093 (3/32) is what most people open them up to on 3 port guns.

[Salt1219 176]

Thank you, they might already be that size then. I will have to take the tube off to properly measure them.

[Eganx 4]

I measured mine with gauge pins and both were .076. Mine was a two port gun though. Also, when measuring make sure there aren't any burrs obstructing the holes

 

So I added another hole @ .082. The gun is was still slightly under gassed, not cycling low brass if the gun wasn't held firmly. So from there I polished the friction points and reprofiled the hammer which solved the cycling problem.

Edited December 4, 2011 by Eganx

[gunfun 3,931]

that sucks. Don't forget to preserve the 30* angle. It ensures that your gun doesn't cheese grater shreds of shot cup and extra powder flakes into your gas block.

 

 

There is also the option of adding a fourth port a bit smaller, and then drilling it up if needed after a test. big holes can let more crud in. IMO a four port gun > a 3 port at the same gas level, because it stays clean longer.

 

Annoying as this sounds, doing it right is a multi step process usually. You don't want to make them too big, so proper procedure is to drill them one step bigger (or add a tiny hole) then re-assemble and test. There are a few people here who went straight to the reccomended size and found themselves way overgassed for the heavy ammo. They made thier guns usable again with adjustable gas plugs that gave more restriction, but their gas blocks plug up earlier, resulting in decreased reliability.

 

A few of the people who moved their own gas blocks for a short gas system, decided to go with big holes or decreased versatility. (generally tuning their gas system to work with high brass only).

Edited December 3, 2011 by GunFun

[pedal2alloy 206]

I think that the 3 holes at .093 are better than the 4 smaller holes, because of the risk of the little bit of barrel within the 4 holes being weak and possibly busting off.

[gunfun 3,931]

Another point is that the increased mass of your bolt with the handle can have 2 negative effects. 1) it requires more gas to get it moving. 2) once it is moving, it has more kinetic energy to slam into the back trunion.

 

Obviously people have been ok with adding mass, but you may as well do your gas tuning after the bolt welding, so that effect #1 is factored in to your adjustments.

[Alpha Kilo 42]

I think that the 3 holes at .093 are better than the 4 smaller holes, because of the risk of the little bit of barrel within the 4 holes being weak and possibly busting off.

 

Has that risk been seen in real life, or just thought up on the net?

[The_Caged_Bird 474]

I enlarged mine to .109, you read that right, three holes at .109. Loved it, damn thing would shoot birdshot from the hip and I had no signs of rear trunnion wear which, I only assume, was attributed to the V-plug...

 

I got tired of cleaning the gas block out after 200 rounds so I sold it, new owner seems to be more than happy with it, he's got other S-12s and I guess that this one is the only one that will eat whatever he feeds it. He loves it. With this new one, I intend to add a fourth hole if it needs it. I'll be using a better plug and puck though that wasn't available at the time that I modded my old S-12 so we'll see what happens...

Edited December 4, 2011 by Caged

[pedal2alloy 206]

I think that the 3 holes at .093 are better than the 4 smaller holes, because of the risk of the little bit of barrel within the 4 holes being weak and possibly busting off.

 

Has that risk been seen in real life, or just thought up on the net?

 

Somebody on the board has mentioned seeing one that has busted thru. Might have been Tromix

[Cely1932 21]

Mine had 3 ports @ 2mm (.079") and I added a 4th @ 2mm also. With V plug it runs everything. My 11 yr old can empty a 20 rd drum of federal bulk from the hip with no failures

[FlameRed 4]

I used .093 also on all three ports. Worked very well with the Walmark bulk cheapie stuff.

[scstrain 8]

This whole gas port issue is such a joke. There is absolutely no reason that the factory can't come up with a standard for the number and size of the gas ports and then get the gas block over them correctly.

 

This whole, "Maybe I will get lucky and get a good one" amazes me.

 

Now go ahead and tell me all the reasons why they can't do this while every other QUALITY company at least tries to. And, I do get the concept that they can sell every one that they ship here no matter how bad quality control is. But, that is a sad state of affairs

[k_ritala 2]

This whole gas port issue is such a joke. There is absolutely no reason that the factory can't come up with a standard for the number and size of the gas ports and then get the gas block over them correctly.

 

This whole, "Maybe I will get lucky and get a good one" amazes me.

 

Now go ahead and tell me all the reasons why they can't do this while every other QUALITY company at least tries to. And, I do get the concept that they can sell every one that they ship here no matter how bad quality control is. But, that is a sad state of affairs

First off, WTF does this have to do with the OP's question? Every post of yours is bitching about the QC at Izhmash. It is what it is. If it's such an issue for you, then go buy an AR and STFU. The S-12 was made to shoot high brass shells, of course you'll run into problems when you try to feed it a bunch of weak bulk ammo. They just take a little bit of work that most anyone can do to run the cheap ammo. Yes, there are some true "vodka specials" out there, but I don't think they are as common as you think.

[Spyder 2]

I don't think that most people realize that we're trying to do things with these shotguns that they aren't designed to do.

 

Bitching about a Saiga not cycling cheap federal low base bird shot is like bitching about your .300 WinMag not being able to fire 30-06 shells. It ain't SUPPOSED to fire them, and if you want it to you're going to have to do some work to it.

[scstrain 8]

I don't think that most people realize that we're trying to do things with these shotguns that they aren't designed to do.

 

Bitching about a Saiga not cycling cheap federal low base bird shot is like bitching about your .300 WinMag not being able to fire 30-06 shells. It ain't SUPPOSED to fire them, and if you want it to you're going to have to do some work to it.

 

That is not the problem. The problem is the fact that you do not know what you will get. If they would have a standard and stick to it (even if they did not work at all) it would be fine. You would at least know what you will get and be prepared to take on the issue.

 

But this it might have one big port, 2 small ports, 3 small ports, or no ports along with it might have the "So called" correct ports but they may be covered by an improperly installed block is rediculous.

 

It could be even a better shotgun if there were a few standards in this area. Not asking for much here............just a little consistancy.

[The_Caged_Bird 474]

I don't think that most people realize that we're trying to do things with these shotguns that they aren't designed to do.

 

Bitching about a Saiga not cycling cheap federal low base bird shot is like bitching about your .300 WinMag not being able to fire 30-06 shells. It ain't SUPPOSED to fire them, and if you want it to you're going to have to do some work to it.

 

That is not the problem. The problem is the fact that you do not know what you will get. If they would have a standard and stick to it (even if they did not work at all) it would be fine. You would at least know what you will get and be prepared to take on the issue.

 

But this it might have one big port, 2 small ports, 3 small ports, or no ports along with it might have the "So called" correct ports but they may be covered by an improperly installed block is rediculous.

 

It could be even a better shotgun if there were a few standards in this area. Not asking for much here............just a little consistancy.

 

You are speaking of the way that we operate in America. The Russians don't operate that way for various reasons, R&D is done by the consumer. Since the S-12 has gotten more popular here in America it has made LEAPS and BOUNDS in reliability. I will say that the Russians have tried to do as much as they can, by even authorizing certain American gun smiths to do warranty work to the S-12s that need it at no cost to the consumer...

 

You have to remember that when you read on this forum it's like reading through time. For example, say this were a Corvette forum, there are MANY different models of Corvette but they are all sports cars. You might have some that would come on here and bitch about the power output from the straight-six and their plastic windows, then you'd have the guys like me who bought from the middle years that would bitch about only having 180 stock horsepower and the lack of an overdrive automatic. The people who have the newest ones would post up about some of the truly wonderful modifications to the design that have been incorporated from the factory.

 

That's what you have here, except there is oftentimes no way to distinguish when we are talking about. Generally the earlier guns have two and four ports while some had three. The Russians have been experimenting with port size for a few years but they still hand build every one so when someone makes a mistake they don't stop the entire line and retool, they leave it for Cadiz to warranty. As of recent, all newer guns have three ports usually close to 3/32" (metric system though) and are also equipped with longer barrel hoods.

 

They are working on becoming more consistent but that will take time. If you do not wish to wait it out, then please, purchase a converted and worked S-12 from any of the vendors listed on this website, they are a little more expensive but you'll have a beast out of the box which is what it sounds like you want. I choose to tinker on my own, the same as I built the engine in my 'vette. It might not be the fastest, but it runs on what I feed it and I know that I built it myself. To each his own.

Edited December 7, 2011 by Caged

[TapeWorm3 104]

I have a 4 hole constantly having cyclic problems no matter what setting or ammo other than 3" so I first bought the TAC47 autoplug which made it useless in cycling so removed the gas block to find my ports were only .062 (1/16") I promptly opened 3 of four to .093 (3/32") and the one closest to the piston to .078 (5/64") .

It took 5 rounds to tune the autoplug and it now cycles everything winchester universal through 1560fps 2 3/4" slugs with no problems.

Thanks to all the info if it was not for the "Test Subjects" we have done and the sharing of the knowledge others like me may have been lost.

[scstrain 8]

Caged, you make some good points. I do see that the Saiga 12 is getting better. Maybe I expect to much.............I will stop beating this dead horse. Thanks for the info.

[gunfun 3,931]

With the corvette though, you can tell just by the model year and the little tag in the door well what engine it has... You don't get one out of 20 1011 ZR1 s that accidentally got a 180 BHP engine. And if that did happen, you wouldn't hear their customer base saying that the owner shouldn't complain because it was only designed to be used as an 1980s car would.

 

The truth is that Izhmash claims their shotgun will eat anything, and most of them do. Once they make that claim, they are obligated to back it up. They aren't selling it as a high brass only tactical gun. They are selling it as a universal use gun.

[The_Caged_Bird 474]

With the corvette though, you can tell just by the model year and the little tag in the door well what engine it has... You don't get one out of 20 1011 ZR1 s that accidentally got a 180 BHP engine. And if that did happen, you wouldn't hear their customer base saying that the owner shouldn't complain because it was only designed to be used as an 1980s car would.

 

The truth is that Izhmash claims their shotgun will eat anything, and most of them do. Once they make that claim, they are obligated to back it up. They aren't selling it as a high brass only tactical gun. They are selling it as a universal use gun.

 

 

True, but Chevy and others have dubbed the Corvette as the "King of Sportscars" through the years. When a 1980 CORVETTE has less horsepower than a stock HONDA CIVIC of any year. It's clearly NOT the King! While I agree on some of your other points, this car and this gun share a lot in common, for instance, there is literally no difference between the C2 frame and suspension and the C3 frame and suspension. Two completely different body styles/generations, yet when you get the bodies off the frames, It's incredibly hard to tell a difference between the two...

 

The point is that it's currently a work in progress, and the guys at the factory who are constantly upgrading and making it better are pretty much learning as they go, just like Harley Earl, Bill Mitchell, Zora Duntov, and John DeLorean, or hell, even John Moses Browning. Like J.M.B. though, once they get the design perfected, it'll be around for decades to come...