First fire issues with SKS. - Gas Tube?

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ronjonjd

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Hi All.

I took my 1950 Russian SKS that I bought last week, out to a cousins farm and fired it for the first time.
Before I did that, I had put on a replacement gas tube (chinese) with a picatinny rail on it.

When I fired the rifle, the slide did not come back far enough to eject the round, and would then get jammed up.
I took it apart, made sure I didn't miss any cosmoline, and put it back together, and the same issue was going on.

I think it is the gas tube and that the piston is not hitting the slide hard enough for it to go all the way back, eject the round and chamber the next one.

Aside from that, the rifle was pretty accurate at 75 yards. I was in the black with almost every shot. Stripper clips kept me loading quickly.

I will be heading back home (2.5 hours away) and putting the original gas tube back on. Alas, I won't be able to test fire it again until I get out to Silverdale or drive back here.

Anyone know if I am on the right track with the diagnosis?

Cheers
Ron
 
That would be one of the things I would look at. I have swapped the gas tubes befor with no proble but you never know. Does it operate smoothly if you manually slide it?. Get some snap caps and try the action. If you don't have snap caps, take the fireing pin out and use live rounds, pointed at a very safe direction. See how it operates. If any problems, then it is in the action.
 
points said:
That would be one of the things I would look at. I have swapped the gas tubes befor with no proble but you never know. Does it operate smoothly if you manually slide it?. Get some snap caps and try the action. If you don't have snap caps, take the fireing pin out and use live rounds, pointed at a very safe direction. See how it operates. If any problems, then it is in the action.
Click to expand...

The rest of the operation is good. After firing, I was tiping the rifle to the right and pulling the slide all the way back and it would eject the shell and chamber the next, and then I'd fire the next round.
Slide is working aside from this issue. I thought maybe there was too much spring tension on the slide spring, so I took the slide spring out and swapped it around on end and that didn't do anything.

What is a snap cap?
 
There may be some crap lodged in the air redirection port which reduces the amount of air that may be getting to the piston.

Get a nice pipe cleaner (the hobby kind), soak it with solvent, and do the ol in and out to make sure its clear of obstructions. You should see the pipe cleaner in the barrel if it is good to go.

Its an awefully simple system. If it cycles smoothly by hand as mentioned above, and the inside of the piston is clean, the above is the only thing that would be causing such an issue.
 
ronjonjd

I had the same problem on a Yugo SKS 59 66, the gas shutoff valve would leak around the gas tube and it would fail to cycle. On the Yugo if you took the gas valve out and flared the shut off valve with a ball bearing it would enlarge the end and stop the gas leaks.

You can test this on your SKS by placing a small rubber o-ring around the groove in gas vent and then install the gas tube. If the o-ring is the correct size and the gas tube fits tightly on the o-ring the rifle should cycle. The o-ring may not last long due to the high pressure but it will seal the end long enough to test for leaks and cycling.

On the Yugo 59/66 corrosive primers and improper cleaning of the gas valve caused the metal to erode the gas valve and it would leak. On yours there are different size gas tubes and you ended up with the the larger and wrong size and it leaks.
 
Last edited:
bigedp51 said:
ronjonjd

I had the same problem on a Yugo SKS 59 66, the gas shutoff valve would leak around the gas tube and it would fail to cycle. On the Yugo if you took the gas valve out and flared the shut off valve with a ball bearing it would enlarge the end and stop the gas leaks.

You can test this on your SKS by placing a small rubber o-ring around the groove in gas vent and then install the gas tube. If the o-ring is the correct size and the gas tube fits tightly on the o-ring the rifle should cycle. The o-ring may not last long due to the high pressure but it will seal the end long enough to test for leaks and cycling.

On the Yugo 59/66 corrosive primers and improper cleaning of the gas valve caused the metal to erode the gas valve and it would leak. On yours there are different size gas tubes and you ended up with the the larger and wrong size and it leaks.
Click to expand...

Thanks Guys.. I'll tinker and let you know what happened. Maybe a midweek trip to silverdale.
 
Use foam bore cleaner, stick your finger on the end of the muzzle and force the foam into the gas vent and gas tube. Don't be surprised when the foam in the gas tube turns blue, vaporized copper must enter the gas system.
 
plinker 777 said:
Dumb question but, you did put the piston (gas rod) in the new tube right?
Click to expand...
As far as I can tell there is only one way that piston goes in. It can't go in backwards.

I got back home and put the stock gas tube back on and I am pretty sure that I figured out what the problem was.
it was the crappy made in China NcStar Gas Tube. The piston was a bit loose in the NcStar, and nice and tight in the stock one. I could feel a bit of suction being created with the stock tube and piston, and in the NcStar tube the piston rattled around just a smidge. Plus the stock tube mounted more snugly and the chinese one was maybe 1/4mm looser.
I'll be heading off to a range as soon as I can to test the theory, but I am pretty sure this will solve it.

here is the pic of the NcStar tube and box.
 
If I convert this to the tactical look, I may just get the plastic housing replacement for the original tube rather than putting on one of these chinese ones.
 
ronjonjd said:
If I convert this to the tactical look, I may just get the plastic housing replacement for the original tube rather than putting on one of these chinese ones.
Click to expand...

I may just keep this one as it is, and buy another one to mess around with. I'm liking the idea of keeping my first one original. I do love the gun though! Amazing bang for the buck!
I do really want to get a scope on it though and I think the only way to do that is to tap the side of the action.
 
ronjonjd said:
As far as I can tell there is only one way that piston goes in. It can't go in backwards.

I got back home and put the stock gas tube back on and I am pretty sure that I figured out what the problem was.
it was the crappy made in China NcStar Gas Tube. The piston was a bit loose in the NcStar, and nice and tight in the stock one. I could feel a bit of suction being created with the stock tube and piston, and in the NcStar tube the piston rattled around just a smidge. Plus the stock tube mounted more snugly and the chinese one was maybe 1/4mm looser.
I'll be heading off to a range as soon as I can to test the theory, but I am pretty sure this will solve it.

here is the pic of the NcStar tube and box.
Click to expand...

I bet that would fit just right in a chinese sks....
 
You can sink a lot of money in a SKS and your not going to get better accuracy clamping sights on parts that "move" around.
Been there done that..............:bangHead:
 
I don't know if I suck with a reddot, but my SKS shoots better with the iron sights lol

By the way, the only sight mount that would actually hold zero on an SKS is to my experience is a Choate mount which requires drilling and tapping the receiver.

A word of friendly advice, keep the money you are planning on spending on an SKS (no matter how little you might think it is), and buy another gun later.
 
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