Someone please explain the adjustable gas piston to me

[Gaddis 1,689]

Yah, it appears to currently be in gas piston setting number 2 right now, bwah, ha, ha...

 

[wickeddeus 0]

Ok, thanks. So it seems that from the factory it comes set to 2 or atleast it did for me. I have now set it to 1 and will go to the range soon to test.

[Ironbarr 0]

To show that most anything can be rationalized:

 

I could believe if a factory shoot test is really done they would start in #1 to prove heavy loads work properly, then shift to softer loads to see if "this" S-12 runs lite loads in#1; then to #2 to prove lite loads, and ending there with minimum handling.

 

Then again...

[Gunfixr 76]

Looks like I'm going to make the multi setting gas nut anyway. I wanted a nice knurled nut that can be moved by hand with no tools, so while I'm at it, I'm going to add one more setting, with half the gas of the #2. I've already done the lathe work, I just need to screw it in and figure out where to make the first position, and from there the other two. I'll post a pic when it's done.

[Gunfixr 76]

Got my adjustable gas knob done. Haven't tested it yet, will be at least a few days till I can get to the range. It has three settings, the 2 standard ones and one that is in between. It is also adjustable by hand, needing no tools. A slight modification is required to the gun, however. The locking pin needs to be removed and the end rounded, and then reinstalled. If this mod isn't overdone, it will still work in the normal fashion with the stock gas knob. It can be done in an electric drill or drill press by chucking the pin and rounding with a file.

It's made of NICUAL, a high performance alloy used by the DOD for high pressure fittings and pipe on submarines. It is quite hard, and absolutely resistant to corrosion. It also has very high wear resistance. While I was at it, I made a new gas piston as well. Why not. Anyway, here's pics:

[USP40 1]

Got my adjustable gas knob done. Haven't tested it yet, will be at least a few days till I can get to the range. It has three settings, the 2 standard ones and one that is in between. It is also adjustable by hand, needing no tools. A slight modification is required to the gun, however. The locking pin needs to be removed and the end rounded, and then reinstalled. If this mod isn't overdone, it will still work in the normal fashion with the stock gas knob. It can be done in an electric drill or drill press by chucking the pin and rounding with a file.

It's made of NICUAL, a high performance alloy used by the DOD for high pressure fittings and pipe on submarines. It is quite hard, and absolutely resistant to corrosion. It also has very high wear resistance. While I was at it, I made a new gas piston as well. Why not. Anyway, here's pics:

Awesome !!!

[IndyArms 10,186]

Thats some FINE WORK, Gunfixr!!!

 

Are those some parts you could make more of?

 

You might find a market, if the prices are right. especially the piston with a USA stamp on it for 922R compliance!

that one alone is a biggie to a lot of folks!!!

 

[Gunfixr 76]

First, I want to run some rounds over it and see how it holds up. I believe it will be fine, but nothing beats actual testing.

I've already had problems with the hand adjustable knob. The material is so hard that it bit into the lock pin and screwed the end up when I was trying to turn it. I've made a new pin out of hardened HSS, and will install it later today and see how it works. The problem is that most of the lock pin overhangs the edge of the knob, which cannot be changed because of the close proximity of the barrel.

 

I'm kind of working on several things at once, as I am i the middle of an S12 conversion also. The customer wants a Tromix stock, mounted via an Ace folding latch and using a Tromix weld on backplate.

[elvis christ 451]

Wanted to give an update. I went shooting on sunday, and started having trouble again, this time using AGP 10 round mags (it seems like the gun has gotten better using the factory mags, buy that might be because they're only 5 rounders, it didn't act up with the AGP until round 7 or 8.)

 

Anyway, I turned the gas tube 180 degrees clockwise, and ran about 20 rounds through it, no problems. I'm still shooting remington light dove shot. I'm going to shoot again probably this weekend, I'll report back and let y'all know what the deal is.

[USP40 1]

First, I want to run some rounds over it and see how it holds up. I believe it will be fine, but nothing beats actual testing.

I've already had problems with the hand adjustable knob. The material is so hard that it bit into the lock pin and screwed the end up when I was trying to turn it. I've made a new pin out of hardened HSS, and will install it later today and see how it works. The problem is that most of the lock pin overhangs the edge of the knob, which cannot be changed because of the close proximity of the barrel.

 

I'm kind of working on several things at once, as I am i the middle of an S12 conversion also. The customer wants a Tromix stock, mounted via an Ace folding latch and using a Tromix weld on backplate.

How is the gas adjustment knob coming along sir?

[Gunfixr 76]

I go to the range later today (Tuesday) to test. I just haven't been able to get there yet, and I did the SRT trigger mod and want to make sure that runs right, too.

[USP40 1]

I go to the range later today (Tuesday) to test. I just haven't been able to get there yet, and I did the SRT trigger mod and want to make sure that runs right, too.

Thank you sir.

[Gunfixr 76]

I went to the range today and got in a little testing. Didn't have a whole lot of time, but was able to make some determinations.

For the testing, I took some of the general use Walmart shells made by Federal. These are loaded with 3 drams of powder. I also took some Winchester field loads, they are also low brass loaded with 3 1/4 drams of powder. These are the shells I use for 3-gun. I took some Remington high brass heavy game loads, which are loaded with 3 3/4 drams of powder. Lastly I took 2 different loads of 3 inch mag shells, both Federal and Remington.

So far I had not fired any 3 inch shells in the gun at all. With the factory gas plug, I had fired the same (same box even) Remington high brass heavy game loads on setting 2, and had tried quite a few of the Winchester low brass field loads. I had fired a few of my skeet reloads, which were 3 dram loads approximating the Walmart special loads.

Of course the high brass loads worked the guns action smartly. The 3 1/4 dram field loads also worked the action well, throwing the hulls well clear, although not as far as the high brass loads. The 3 dram loads that had been tried did cycle the action, although the hulls just barely cleared the receiver and fell right beside the shooter.

The new gas plug was built to achieve three things: first, it was to be adjustable without tools. Second, the end facing the gas piston, or "puck", was designed to better channel the gases and more efficiently utilize them, bringing them to bear on the center of the piston, so as to push straight back. To this end, the facing end has a counterbore in it as opposed to a centered stud, like the original does. Third, it was to give a setting in between the 2 original settings, as when firing 2 3/4 inch slug loads and high brass heavy game loads seem a bit punishing to the gun and shooter. While it has been established that this won't necessarily hurt the gun itself, why batter it any more than necessary.

I didn't set up a target or do any patterning, as I didn't have much time and this was a function test. I didn't get to fire a significant number of rounds, so I just noted ejection and used that as the criteria for smartness of action.

For purposes of this description, setting 1 is the smallest amount of gas, the same as the original plug. Setting 2 is the in between setting, and setting 3 is the most gassed setting, as in setting 2 on the original.

For setting 1, I fired a 5 round box of the Remington 3 inch mag shells through without a hitch. A noteable muzzle flash was evident, and the action was cycled solidly, with the shells kicking out about 8-10 feet away. Of the Federal 3 inch shells, only 3 were fired. Of these, 2 failed to eject, with the bolt being stopped having the open end of the shell stuck on the end of the chamber. Setting 1 would appear to need a little more opening up. I purposefully made it small just for this.

For setting 2, the high brass heavy game loads fired without incident, having fired 5-10 shells, they ejected about 8-10 feet away. The low brass standard game loads also cycled the action well, kicking the hulls about 6-8 feet away. The low brass general purpose shells did cycle, but just "dribbled" the hulls out of the action.

For setting 3, the low brass standard game loads cycled the action smartly, kicking the shells approx. 8 feet away evenly. The general purpose low brass shells, the "Walmart specials", cycled the action smartly as well, kicking the hulls about 6-8 feet away.

 

As far as achieving my goals, the knob is adjustable by hand. It does also give better results with the very weak shells. Once final tweaking is done with setting 1, it will work the 3 inch shells with just enough gas, but without a lot more, which it may have done already, but this was not the specific reason for this project. I plan to actually reduce the second setting some, as it is really for the heavy 2 3/4 inch shells. It won't work with the weak 2 3/4 inch shells, but will be easier on both the gun and shooter with heavy 2 3/4 inch shot loads and slugs. This, and no tools adjustment, are the main goals.

 

If I were to make these, I may end up changing the material I made it from, as this was difficult to work with. The knurling took about as long as all the rest to do, as the material is so hard and tough.

Edited April 23, 2008 by Gunfixr

[Cobra 76 two 2,677]

Good work man!

[USP40 1]

Excellent!!!

[GTwannabe 1]

Pretty sweet! Changing gas settings in the field can be a pain, as powder residue gums up the threads.

 

Is it possible to add a 4th gas setting? OFF would be nice.

[Gunfixr 76]

I don't know if OFF could be added. When the gas plug is turned in all the way, the inside end is right at the point of cutting off the gas hole in the block, but not quite. Perhaps it could be done, but it would require most of a turn past this point, which would bring around one of the other settings and negate the OFF part. Maybe, I don't know. It wasn't something I was really thinking of doing, so I didn't try it.

 

 

Later today, I will make some adjustments, openng the smallest setting a little, and closing the medium setting a little. Soon, I will get it back to the range for another test. Saturday I have a 3-gun match, so it may not be this weekend. I plan on running the cheap Walmart shells, to give them a more thorough test.

 

 

Because of the redesign of the end where it meets the piston, gas fouling shouldn't get into the threads as much, but time will tell. Since the end is counterbored, most of the gas should be trapped and forced directly into the puck, instead of going around the sides and back to the threads.

[kellysguy 1]

Be careful not to increase the total volume more than the factory adjuster.

[Gunfixr 76]

Be careful not to increase the total volume more than the factory adjuster.

 

I didn't. I can't really, as I have made no modifications to the gas ports, so it can get no more gas than that, anyway.

 

Had a 3-gun shoot yesterday, shot the cheap Walmart Federal shells for the match. They worked fine. Shot some Winchester field loads on one stage and had some didn't want to chamber, but I think it was the shells.

 

Gonna try to get my adjustments made on the smaller settings and get them to the range soon.

[USP40 1]

Be careful not to increase the total volume more than the factory adjuster.

 

I didn't. I can't really, as I have made no modifications to the gas ports, so it can get no more gas than that, anyway.

 

Had a 3-gun shoot yesterday, shot the cheap Walmart Federal shells for the match. They worked fine. Shot some Winchester field loads on one stage and had some didn't want to chamber, but I think it was the shells.

 

Gonna try to get my adjustments made on the smaller settings and get them to the range soon.

Thanks for the update.

[DavePAL84 1]

When replacing/reinstalling the puck, is there a particular side to go in first?

 

I'd like an answer to this as well

[Cobra 76 two 2,677]

When replacing/reinstalling the puck, is there a particular side to go in first?

 

I'd like an answer to this as well

No it doesn't matter.

[Gunfixr 76]

Well, I made some adjustments to settings 1 and 2, and finally was able to do some testing Sunday. As setting 3 already proved to work very well, it was the one designed to work all those weak, cheap shells that sometimes give trouble, I had not made any changes to it.

Setting 2 worked with some of the weaker shells, and worked firmly with heavy, high brass, 2 3/4 inch loads, so I actually reduced it just a little. Setting 1 was for 3 inch shells, and worked with one brand, but not another, so I increased it just a little.

 

On setting 2, which is for heavy 2 3/4 inch loads, it worked good, having less recoil than before with the same loads as before, having about the same felt recoil as the weak general purpose shells, and ejecting similarly. I feel that it is pretty much GTG.

 

Setting 1 was tried with Federal 3 inch 00 buckshot, Remington 3 inch #4 buckshot, and Winchester Supreme 3 inch #4 buckshot. Previously, I had only tried the Federal and Remington loads. Also previously, the Remington loads worked fine and the Federal loads didn't quite cycle. Now, all three loads cycled fully. The federal loads are noticeably weaker than either the Remington or Winchester loads, and the Remington loads were hotter than the Winchesters, but not by a whole lot. Not a lot of rounds were used, a full box of five of each (I ain't made of money), and they were simply fired through quickly and felt recoil and positiveness of ejection were noted, the same as before.

 

I think that perhaps setting 1 may have been increased a little too much, but I am not positive on this. Recoil and ejection were quite strong with the Remington and Winchester shells. But the earlier cut left the Federals not working. There may simply be enough difference in the load power of the brands to make it impossible for the perfect setting, and I'm not going to try for a fourth setting. As originally designed, it works well with all 3 inch loads on setting 1, and I have that now, with the added ability to work with the weaker shells that often don't work, and the ability to change the settings just by grabbing the knob and rotating it.

[USP40 1]

Well, I made some adjustments to settings 1 and 2, and finally was able to do some testing Sunday. As setting 3 already proved to work very well, it was the one designed to work all those weak, cheap shells that sometimes give trouble, I had not made any changes to it.

Setting 2 worked with some of the weaker shells, and worked firmly with heavy, high brass, 2 3/4 inch loads, so I actually reduced it just a little. Setting 1 was for 3 inch shells, and worked with one brand, but not another, so I increased it just a little.

 

On setting 2, which is for heavy 2 3/4 inch loads, it worked good, having less recoil than before with the same loads as before, having about the same felt recoil as the weak general purpose shells, and ejecting similarly. I feel that it is pretty much GTG.

 

Setting 1 was tried with Federal 3 inch 00 buckshot, Remington 3 inch #4 buckshot, and Winchester Supreme 3 inch #4 buckshot. Previously, I had only tried the Federal and Remington loads. Also previously, the Remington loads worked fine and the Federal loads didn't quite cycle. Now, all three loads cycled fully. The federal loads are noticeably weaker than either the Remington or Winchester loads, and the Remington loads were hotter than the Winchesters, but not by a whole lot. Not a lot of rounds were used, a full box of five of each (I ain't made of money), and they were simply fired through quickly and felt recoil and positiveness of ejection were noted, the same as before.

 

I think that perhaps setting 1 may have been increased a little too much, but I am not positive on this. Recoil and ejection were quite strong with the Remington and Winchester shells. But the earlier cut left the Federals not working. There may simply be enough difference in the load power of the brands to make it impossible for the perfect setting, and I'm not going to try for a fourth setting. As originally designed, it works well with all 3 inch loads on setting 1, and I have that now, with the added ability to work with the weaker shells that often don't work, and the ability to change the settings just by grabbing the knob and rotating it.

[hobbyshooter 59]

Well, I made some adjustments to settings 1 and 2, and finally was able to do some testing Sunday. As setting 3 already proved to work very well, it was the one designed to work all those weak, cheap shells that sometimes give trouble, I had not made any changes to it.

Setting 2 worked with some of the weaker shells, and worked firmly with heavy, high brass, 2 3/4 inch loads, so I actually reduced it just a little. Setting 1 was for 3 inch shells, and worked with one brand, but not another, so I increased it just a little.

 

On setting 2, which is for heavy 2 3/4 inch loads, it worked good, having less recoil than before with the same loads as before, having about the same felt recoil as the weak general purpose shells, and ejecting similarly. I feel that it is pretty much GTG.

 

Setting 1 was tried with Federal 3 inch 00 buckshot, Remington 3 inch #4 buckshot, and Winchester Supreme 3 inch #4 buckshot. Previously, I had only tried the Federal and Remington loads. Also previously, the Remington loads worked fine and the Federal loads didn't quite cycle. Now, all three loads cycled fully. The federal loads are noticeably weaker than either the Remington or Winchester loads, and the Remington loads were hotter than the Winchesters, but not by a whole lot. Not a lot of rounds were used, a full box of five of each (I ain't made of money), and they were simply fired through quickly and felt recoil and positiveness of ejection were noted, the same as before.

 

I think that perhaps setting 1 may have been increased a little too much, but I am not positive on this. Recoil and ejection were quite strong with the Remington and Winchester shells. But the earlier cut left the Federals not working. There may simply be enough difference in the load power of the brands to make it impossible for the perfect setting, and I'm not going to try for a fourth setting. As originally designed, it works well with all 3 inch loads on setting 1, and I have that now, with the added ability to work with the weaker shells that often don't work, and the ability to change the settings just by grabbing the knob and rotating it.

This looks and sounds like a great potential product. I'll be keeping my eyes on it, and I think it deserves it's own thread.

[bigjimcalhoun 0]

Alright, I just got a my Saiga 12 recent and it came out of the box with the 2 at 7 o'clock and the 1 is at 3 o'clock if I'm looking down the barrel. Does this mean that the regulator is set to the 2 setting which should be used for light load or the 1 setting for heavy load? I just want to be sure since it's a new toy. If anyone has pictures that would be great. Thanks.

 

 

Edit: Mine is set just like the one in this picture.

 

 

Hi - newbie here...

If I have the gas setting at #2 like the picture above, which way do I turn it to get to #1?

 

thank you

[waltham_41 52]

Clockwise to 1 if it will go all of the way. Then if you need to go back to number 2 go counterclockwise, then clockwise back to 1. Always go back and forth, never just keep screwing out when changing

[bigjimcalhoun 0]

Clockwise to 1 if it will go all of the way. Then if you need to go back to number 2 go counterclockwise, then clockwise back to 1. Always go back and forth, never just keep screwing out when changing

Thanks bro - that is what I thought. I don't think it will make it to "1" completely. It comes close but I don't want to force it. Any recommendations?

[BobAsh 582]

Just back it out to #1.