Author Topic: Shooting without Gas Piston  (Read 3287 times)

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bjlatt

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Shooting without Gas Piston
« on: January 13, 2012, 03:39:00 PM »
Is it possible/safe to fire an SKS with the gas piston removed?  Would the rifle act like a bolt action?

tsc

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Re: Shooting without Gas Piston
« Reply #1 on: January 13, 2012, 05:07:00 PM »
I don't have first hand knowledge. But if my logic is correct, it should be like a single shot/bolt action. The gas, instead of pushing the gas piston, will just escape from the holes in the gas cylinder and out of the barrel behind the bullet.

BillyBang

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Re: Shooting without Gas Piston
« Reply #2 on: January 13, 2012, 05:18:07 PM »
I don't have first hand knowledge. But if my logic is correct, it should be like a single shot/bolt action. The gas, instead of pushing the gas piston, will just escape from the holes in the gas cylinder and out of the barrel behind the bullet.

Not to mention that without the piston blocking the gases from entering
the piston stem channel, you could end up with a face full of hot,
high pressure gases and debris coming out the receiver area.

If you remove the piston, you then have to remove the gas tube and
plug the gas port with a threaded plug for it to be safe.

Of coarse with the M59/66's you can turn the gas valve to the off position.





jdscholer

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Re: Shooting without Gas Piston
« Reply #3 on: January 14, 2012, 02:41:01 AM »
I tried something a little different to disable the gas system of my Norinco, and actually took pictures.
As you can see, I used a very stiff compression spring behind the piston head. The spring ran the length of the gas tube down to the smaller diameter stops it, and you can see that it takes a couple of inches of compression to install the gas tube.  You can also see the fitted plug I made to fill the recess in the gas block and plug the gas port.  I figured that the powerful spring tension would keep the plug in place and effectively stop the piston rod from any substantial rearward travel. Introducing the "jd SKS Gas Block System".!!
Incredible!! Right?  --- WRONG :cry:  There must be incredible pressure we're working with here, because after about five shots, my "powerful spring" was collapsed to the point where the action cycled almost as normal.  Total failure and back to the drawing board.  jd 
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scizm

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Re: Shooting without Gas Piston
« Reply #4 on: January 14, 2012, 08:25:55 AM »
my very first sks some 20 plus years ago was a norinco paid like 75 bucks for it from a pawn shop. n.i.b. and had no piston i shot it and lived to tell the tale.
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ruston61

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Re: Shooting without Gas Piston
« Reply #5 on: January 14, 2012, 09:25:19 AM »
 Well tel the tale did you or did you not get a face full of hot gas etc..??
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BillyBang

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Re: Shooting without Gas Piston
« Reply #6 on: January 14, 2012, 09:41:16 AM »
my very first sks some 20 plus years ago was a norinco paid like 75 bucks for it from a pawn shop. n.i.b. and had no piston i shot it and lived to tell the tale.

Must have still had the op rod installed.


bjlatt

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Re: Shooting without Gas Piston
« Reply #7 on: January 14, 2012, 10:54:07 AM »
Thanks for the replies.  I read that somewhere, don't remember where, but I wanted more that one opinion on this.  I thought you would get blowback gas in the face, but I don't know everything.

BillyBang

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Re: Shooting without Gas Piston
« Reply #8 on: January 14, 2012, 11:07:22 AM »
That's one thing people don't know or tend to forget.
50,000 psi pushing a projectile @ 2,400 fps
is a controlled/contained explosion.
Channeling a portion of that pressure through a 1/10th of an inch
dia hole is enough to violently slam the action back during firing.
Firearms are designed to work with all components
installed and in good working condition.
People screwing around with them is when you hear about people getting hurt.

*DO NOT modify anything unless you understand what you are doing*.




jdscholer

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Re: Shooting without Gas Piston
« Reply #9 on: January 14, 2012, 11:10:29 AM »
I would still like to disable the system, for when I'm shooting my reloads.  Next time, in stead of a spring I'll use a solid bushing to prevent the piston from traveling back. 
BillyBang, have you ever seen anyone install a gas valve on non yugo SKS's?  jd
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BillyBang

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Re: Shooting without Gas Piston
« Reply #10 on: January 14, 2012, 11:16:07 AM »
No,
But I think it was Fragger that threaded the inside of a gas block
on a Chinese SKS and used a pipe plug on one of his.
IIRC: They left the gas tube off but you could remove the plug,
reinstall the gas tube and use normally at any time.

jdscholer

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Re: Shooting without Gas Piston
« Reply #11 on: January 14, 2012, 11:20:19 AM »
Hmmm.  After witnessing the amount of pressure that operates this system, I don't know that I'd want that pipe plug (even threaded in) pointed at my ruggedly handsome face.  jd
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On my worst day, I may find someone whose day I can improve.

ARYLIOA

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Re: Shooting without Gas Piston
« Reply #12 on: January 14, 2012, 12:28:12 PM »
Not to mention that without the piston blocking the gases from entering the piston stem channel, you could end up with a face full of hot, high pressure gases and debris coming out the receiver area.

I haven't really thought about it, knowing that Simonov had it all worked out, but where do the gasses normally exit the gas system?  Do they "run out of steam" and the mechanism just push them back out the gas block opening, or do they vent elsewhere, or just dissipate as they cool?

Have any of the folks who modify the gas port had any unexpected failures of the gas assembly due to increased pressure?

jdscholer

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Re: Shooting without Gas Piston
« Reply #13 on: January 14, 2012, 01:32:56 PM »
Not to mention that without the piston blocking the gases from entering the piston stem channel, you could end up with a face full of hot, high pressure gases and debris coming out the receiver area.

I haven't really thought about it, knowing that Simonov had it all worked out, but where do the gasses normally exit the gas system?  Do they "run out of steam" and the mechanism just push them back out the gas block opening, or do they vent elsewhere, or just dissipate as they cool?

Have any of the folks who modify the gas port had any unexpected failures of the gas assembly due to increased pressure?

Looks to me like the most likely escape route for the gas pressure is back out the gas block.  The piston doesn't travel back far enough to allow much to escape through the gas tube vents.  The operating rod limits the travel of the piston rod to about an inch, so there simply isn't anywhere else for it to go.  It is obvious to me however that the gas block, and gas tube are designed to contain a very high pressure spike.  jd
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On my worst day, I may find someone whose day I can improve.

Cgrilla

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Re: Shooting without Gas Piston
« Reply #14 on: January 14, 2012, 11:18:12 PM »
<i> Well tel the tale did you or did you not get a face full of hot gas etc..??</i>

Would that make it kind of like shooting an AR? Sorry but that is why  I unloaded my AR. I got sinusitis from breathing the backwash.