SKS misfiring after new NCStar gas tube replacement...

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ADHDCanuck

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My original gas tube got a bit pitted from corrosive ammo use (didnt remember to clean the gas tube quickly enough...) so I replaced it with a new one from NCStar. Required a little filing to make fit like most of their stuff...

Now it's having ejection issues... not getting consistent semi automatic fire.. the ejected brass is getting caught in the bolt, which is jamming the next rounds... so it requires manually raking the action to clear it and sometimes re-loading.

I had it apart and the piston/tube (with a thumb over the hole) doesnt make a good seal like the original did... might need a little grime in there from usage to stiffen it up?

I gave it a good disassembly and cleaning after... dont want to be leaving corrosive ammo residue in there.

Thoughts?
 
the theory im currently working on is the pressure is different with the different seal with the new tube and piston... and the rate of return is different on the bolt.... its screwing up the feed and not throwing the brass out at the right rate so its getting caught.

my SKS buddy tells me it needs to be worn in, by not cleaning the gas tube. but corrosive ammo makes that a bad idea.
 
Could always shoot non corrosive for a while and see if it seats in? Do ncstar sell pistons maybe they need to be matched.
 
i ordered a pile of SVT40s.. and in the order i picked up an original new gas tube for the sks.. so i'll probably install that.

and meanwhile, i'll try and put a hundred rounds of noncorrosive thru it with the ncstar and see if theres any improvement. i jsut really like the red-dot i got on there, it allows me to use the original iron sights still because the rail is hollow in the middle and the red dot is awesome.
 
There was a thread similar to this a while ago and it seems that the inner diameter of the NCStar tubes is a little too big. If you put the piston in and cover the back end with your thumb, does the suction hole the piston in the new tube? if there's rattle room around the head of the piston and the inside of the tube then you have too much gas passing past the piston head, which won't provide enough force to cycle the gun.
 
its a 1955 manufacture chinese SKS not a norinco.
and the piston does not produce suction to hold the piston in the gas tube with my thumb over it..

and yes lever arms :) I could not BELIEVE the prices, so i got a russian sks as well... figured i've teethed on this one a bit
 
Last edited:
EL34/6L6 said:
Yours is likely a Chinese "Type 56" but not a 1955 production. 1956 is the year China started making the SKS after purchasing the tooling from Russia. There are many factors in dating a Chinese SKS actually.
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oh! thanks.. I treat it like a fun tool... by no means a collectors item or show weapon.... just fun on the range/utility grade... i have a proper russian one coming thats much nicer... that one will never see corrosive ammo.
 
Canadiankeeper said:
ok ok ok, here is the problem !

NC star....

Take it off, your good to go... why did you change in the first place ?
Click to expand...

i changed because i failed to clean my gas tube and piston following a day out shooting about 500 rounds... i cleaned the rest...
a friend with an SKS warned me the following week about reading that the corrosives eat the gas tube.

So i cleaned it and it was messy inside... close inspection under lights turned up some pitting inside.. i cleaned it and treated it with anticorrosives... but i thought well, why not order the replacement gas tube.. and use the red dot sight my friend wanted to sell me for cheap.
 
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