gas pistion coating?

[Greenhorse six]

Do all chinese SKS's have a course black coating?I'am thinking this may be causing my FTEs.

If I turn the pistion around it will only go half way down the fat part of the tube.

this was on it before it was ever fired, so its not carbin build-up.

 

[eos]

Do all chinese SKS's have a course black coating?I'am thinking this may be causing my FTEs.

If I turn the pistion around it will only go half way down the fat part of the tube.

this was on it before it was ever fired, so its not carbin build-up.

Piston head should be chromed. Piston shaft is blued. Coarse black coating sounds like dirt or corrosion or perhaps a very poorly refinished, well used piston.

Piston does not travel the full length of the tube when cycling and does not fit when reversed.

 

[poweredbybeer]

Maybe there's a burr on one of the gas vent holes? Or the gas tube is bent/kinked/dented? How much of the rod is sticking out the back end of the gas tube (the skinny end) when the piston is fully bottomed?

 

[Greenhorse six]

the coating has a sand like texture to it.

I didn't mean to sound like an idiot about reversing the gas pistion,I wanted to know if the head of the pistion was free to travel the length of the fat part of the gas tube. mine only go's less then half way.

 

[eos]

the coating has a sand like texture to it.

I didn't mean to sound like an idiot about reversing the gas piston,I wanted to know if the head of the piston was free to travel the length of the fat part of the gas tube. mine only go's less then half way.

Piston heads are fitted to the rifle during initial build. This is why you find them numbered to the receiver number on an original, unrefurbed carbine.

I suspect that less than milspec care is taken when rebuilding for civilian sales.

It's not unusual to find heavy corrosion and carbon build up inside the gas tube. This too, can restrict the movement of the piston head.

Your piston might be pitted, but a "sand" like texture tells me the new finish was hastily applied over a well rusted piston.

Not a crisis, you can find mint/excellent pistons (or other parts) for cheap on ebay or from Lever Arms in Vancouver.

 

[bobc]

my norinco sks has a smooth shinny black teflon like coating on the piston rod ,maybe some type of solvent you used attacked the coating and made it rough ,i would recommend removing the rest of the coating and polishing the rod. just my .02

 

[Greenhorse six]

It was like that new, thinking it's like eos said,because there is some pitting on it after the coating started to wear with use.

 

[poweredbybeer]

Is this pitting you're talking about on the piston head itself, or the rod? I took my gas tube off and checked the piston travel, it only extends out the back end of the gas tube about 1.5", max (push the op-rod as far as you can against its spring, its travel is even less than that of the gas piston!).

 

[Greenhorse six]

The face of the pistion is covered or coated,there's some ,a fleck or two in the groves,but mostly on the tail.

Its smoothed out quite bit with use.

About the pistion rod travel,yeah, it only has to travel far enough to start the bolt carrier rearward .some time I wounder how I've lived to be so old.