Plugging gas vent

[jonezz88 0]

Has anyone out there tig welded gas vent shut to help bird shot cycle.

[Etek 32]

It's there for a reason, don't do it.

[jonezz88 0]

Thats what i thought but i was reading up on this link http://earthseaphoto.com/SagaofMySaiga.htm And he shows it done to his?

[BUFF_dragon 3]

my first thought when reading that was "WHAT F-Ng WORLD ARE YOU ON!!!" its there as a pressure release and if you're having that much problem with low gas, send it to Tom at Cadiz and let him FIX it instead of blowing up and ruining your gun.....

 

HOLY CRAP if someone actually welded that and didn't give the gas a safe place to go, they're a bloomin nut-job.....

get a gas plug.....dayum

[Will486 7]

+1 for CGW. Enlarge the gas ports if you need to cycle birdshot. Ive heard of people closing up the vent as well, but overcompressed gas inside a sealed steel cylinder is literally the definition of a decent pipe bomb.

[mgconnor13 206]

"over compressed gas inside a sealed steel cylinder is literally the definition of a decent pipe bomb."

 

+1 to what he said

Edited January 25, 2010 by Rusty truck

[6500rpm 670]

That holes at the back of the gas block, behind the piston (puck). Shouldn't be anything there but blow by to start with in my mind. The puck stops it's travel at the back of the bore, the innertia produced in that little 1" stroke drives the bolt carrier/extension all that distance. I really don't know the reason why the vent is there, but I can't see a benefit to plugging it. As far as I know, none of the SBS manufacturers on the board touch it and they look for everything they can get.

[BUFF_dragon 3]

I know that when I tore my gun down to convert that there was an awful lot of 'gunk' that had come outta that little hole and ended up in my handgaurd.... dont think I would've wanted any of it to stay inside the gun and possibly blow back into the reciever

[G O B 3,516]

At the end of the floating piston's travel, the expanding gases need to go SOMEWHERE. Leave the bleed down hole alone.

[skiboatsp 111]

At the end of the floating piston's travel, the expanding gases need to go SOMEWHERE. Leave the bleed down hole alone.

 

Ditto

[sacsucks 3]

So with the help of a gunsmith and full machine shop, I converted 2 Vodka Specials to something that now have worked for a good year with regular use and thousands of rounds through them with no explosions or issues. Sure I could have sent them in to Cadiz, but I wanted to learn how to do this myself and it was part of what I expected when I got into this type of gun. Hope some of you take the risks to learn so its not just something you send out to get done.

 

As controversial as my decision to seal that side vent under the handguard may be, this is in regards to fixing a Vodka special, not for good working guns. My smithie recommended it and it helped a lot on the two s12s we worked on which we tested before and after. In the case of the 21 inch barrel, the hole left uncovered resulted in weak ejects. Tiging it shut helped on that gun to ensure proper ejects.

 

Cobra mentioned when I posted my article that he covered his with scotch tape and it didnt even blow it off when shooting, even though he does not agree with my decision to plug the hole. That is sure not a lot of pressure escaping from that port so I think some of you are making a big deal about blow ups and dont know what you are talking about.

 

The gas tube and gas system is so loose on my guns and is far from a sealed system that there is no risk of the thing going boom for that port being sealed alone. Take off the dust cover and try to shake your gas tube. It probably moves a bit if its a factory model that has not had the gas block pushed on tighter. Look at the design of the gas system of the s12 or any ak. There is plenty of space in there for gas to escape.

 

The two s12's we did this to have had thousands of rounds through them, even magnum slugs with no issues, so I think thats testament that its fine. Very little pressure is gained from plugging that hole. Shooting bird shot has a lot more to do with the # of gas ports than the side port as I noted in my article. I suggest you read through the whole thing before you put ur 2 cents in!

Edited January 25, 2010 by S.A.C. Sucks

[jonezz88 0]

It doesn't make sense when you guys say that the expanding gas needs some where to go or that all that gas will build up and turn in to a giant pipe bomb. I dont think you quite know the physics of the gas system on these rifles. If the hole was plugged, any excess pressure will just bleed back through the port holes it entered and out the end of the barrel. I think the main reason of this vent is for any debris and soot that makes it through the ports has somewhere to go. As long as you cleaned this out regularly i dont see any reason not to plug it. My only question is if any body else did this and noticed a difference in performance and if it is worth going through with.

[Will486 7]

Oh, I understand that. However I also understand that every other piston-operated rifle on the modern market features a relief valve of some type, be it your simple AK style holes in the cylinder or advanced one-way valves on piston driven ARs. The relief valve is an integral part of the design, and is there for a reason. I see no reason to plug it up, as it could not possibly improve performance. As one user posted above, by the time the gas reaches the relief valve (which isnt really a valve, but eh..) in an S12, the piston has already completed its cycle so closing that port would not improve the function of the rifle in any manner. During rapid fire, if the gasses retreating back into the barrel were not given ample time and an opportunity to make it out the muzzle, you could certainly be dealing with a pipe bomb. If you need to cycle birdshot, look into enlarging the gas ports from the barrel to the gas block, but do not plug the relief valve.

Edited January 26, 2010 by Will486

[vitamink 90]

"Plugging gas vent"

 

christ... You know, every time i click on one of these threads thinking its gonna be about porn i'm always disappointed to find out that its some gun issue. Lure me in then do a "bait and switch". This has got to stop.

[Will486 7]

"Plugging gas vent"

 

christ... You know, every time i click on one of these threads thinking its gonna be about porn i'm always disappointed to find out that its some gun issue. Lure me in then do a "bait and switch". This has got to stop.

 

[skiboatsp 111]

So with the help of a gunsmith and full machine shop, I converted 2 Vodka Specials to something that now have worked for a good year with regular use and thousands of rounds through them with no explosions or issues. Sure I could have sent them in to Cadiz, but I wanted to learn how to do this myself and it was part of what I expected when I got into this type of gun. Hope some of you take the risks to learn so its not just something you send out to get done.

 

As controversial as my decision to seal that side vent under the handguard may be, this is in regards to fixing a Vodka special, not for good working guns. My smithie recommended it and it helped a lot on the two s12s we worked on which we tested before and after. In the case of the 21 inch barrel, the hole left uncovered resulted in weak ejects. Tiging it shut helped on that gun to ensure proper ejects.

 

Cobra mentioned when I posted my article that he covered his with scotch tape and it didnt even blow it off when shooting, even though he does not agree with my decision to plug the hole. That is sure not a lot of pressure escaping from that port so I think some of you are making a big deal about blow ups and dont know what you are talking about.

 

The gas tube and gas system is so loose on my guns and is far from a sealed system that there is no risk of the thing going boom for that port being sealed alone. Take off the dust cover and try to shake your gas tube. It probably moves a bit if its a factory model that has not had the gas block pushed on tighter. Look at the design of the gas system of the s12 or any ak. There is plenty of space in there for gas to escape.

 

The two s12's we did this to have had thousands of rounds through them, even magnum slugs with no issues, so I think thats testament that its fine. Very little pressure is gained from plugging that hole. Shooting bird shot has a lot more to do with the # of gas ports than the side port as I noted in my article. I suggest you read through the whole thing before you put ur 2 cents in!

 

There are major differences between a standard AK piston driven gas system and the tappet system in a s12 shotgun

 

s12 tappet does move to the back of the gas block and in effect seals off gases.

 

Yours apparently work great, nobody is saying they don't, but s12's can be tuned to run properly without plugging it.

 

As cobra states with the scotch tape test, very little gas escapes so how does plugging it make so much difference in functioning?

 

Not trying to start anything just my own 2 cents.

Edited January 26, 2010 by saigatechusa

[Azrial 1,091]

+1 for CGW. Enlarge the gas ports if you need to cycle birdshot. Ive heard of people closing up the vent as well, but overcompressed gas inside a sealed steel cylinder is literally the definition of a decent pipe bomb.

Well this is not likely to make a Bleivy, but it is a completely bad idea. The overpressure will leak out around the piston if it has to, and I believe that this will cause accelerated wear as the piston is pushed harded to the sides of its cylinder. This problem would become more exacerbated by rapid firing.

 

In short, it is s stupid idea, don't do it.

[corbin 621]

I'm by no means a Saiga expert, but here's what I've heard from more knowledgeable folks than me:

 

 

The hole is mainly to allow for air behind the piston (puck) to get out of the way so it doesn't act as a buffer to slow down the puck's momentum when you fire the weapon. After the puck is at it's rearward most position, yeah, some of the gas (which has already done its job) can bleed out....but that's not it's primary function.

 

 

Again, don't take what I say as gospel. I could be wrong. Everything I've learned up to this point has me convinced of this however.

 

 

Hope this helps

 

 

Corbin

[David Mark 2,452]

The hole is mainly to allow for air behind the piston (puck) to get out of the way so it doesn't act as a buffer to slow down the puck's momentum when you fire the weapon.

 

 

This makes a lot of sense and is the best explanation for the port I have heard yet.

 

 

[skiboatsp 111]

This is what can happen if you plug dat hole

 

bleve

[G O B 3,516]

Gas has mass. mass in motion = inertia. With the vent hole and since a object in motion (gas) tends to stay in motion,due to it's inertia. A gas vent will reduce inversion into the barrel of the gas that has entered and expanded in the volume of the cylinder. The factory thought that this vent was important enough to reduce their profit on every one of the shotguns they produce by the expense of the separate machining operation it takes to provide that vent.

 

Go ahead Eisenstein and weld them up, just don't touch mine.

[shades_of_grey 1,092]

Gas has mass. mass in motion = inertia. With the vent hole and since a object in motion (gas) tends to stay in motion,due to it's inertia. A gas vent will reduce inversion into the barrel of the gas that has entered and expanded in the volume of the cylinder. The factory thought that this vent was important enough to reduce their profit on every one of the shotguns they produce by the expense of the separate machining operation it takes to provide that vent.

 

Go ahead Eisenstein and weld them up, just don't touch mine.

 

Exactly. Every single feature on a weapon based on the AK design has a very specific purpose. These are no-frills firearms, (part of the reason I love em). That vent hole has a purpose significant enough to warrant its inclusion on every Saiga shotgun Izhmash makes.

 

If you wanna second-guess em, (from a position of relative ignorance), it's your funeral.

[jdtravers 637]

At the end of the floating piston's travel, the expanding gases need to go SOMEWHERE. Leave the bleed down hole alone.

 

Ditto

 

Close, but it is there so COMPRESSING gas can escape, expanding gas is moving the piston towards the bleed hole. The piston/puck is moving against the OPROD within a cylinder so it allows the gas as it compresses to release to atmosphere and prevent suction/vacuum on return of the piston to the top of the stroke. Welding the hole shut would cause a minor hinderence on performance not help it. The systems tolerences will allow blow-by so it is not detremental to performance/safety. Some guns just run better than others, those guns that were welded shut would have run just as well, actually a little better if they were left alone. It is a matter of bringing everything into original design specs (gas system, recoil system, timing the bolt), just like blueprinting an engine. It really helps if you know what you are doing.

 

Regards,

 

Jack Travers

JT Engineering