CZ 858 piston pitted

Cteve

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Hi guys, I recently purchased a new CZ 858 off the EE and after receiving it in the mail I did an initial breakdown and cleaning to find that the piston had a bunch of pitting on it. I contacted the seller and he has told me that this is how they come from the factory. Is this true? Please share any info you have regarding pitting on a CZ 858 if you have any thanks.
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That is from improper cleaning after using corrosive ammo mine is spotless and I always stay away from corrosive.If you know how to clean the gun properly you will not have any issue.Come that way? what a load of bs Should be allright I have seen a lot worse but keep your eye on it..hope this helps...
 
Yeah I've seen them come new from gunshops with pitting even in the barrel. Depending on what version it is, some were made with used parts, some with NOS parts, some with a mix.
That is not bad pitting at all though in your pic and would not affect anything.
 
That hardly looks like pitting. Take some steel wool and oil to it, I bet it comes right off.
 
Thanks fellas, as for the steel wool I did do that before I took the picture, it was a lot worse before but thanks for input. I will just suck it up because you are right it doesn't affect the performance of it. I just figured a new gun wouldn't come with internal or external parts like this.
 
Don't forget, there are no "new" cz-858's. The Cz-858's were made from surplus parts, using new barrels, in the non-restricted case. It's not unheard of to have less than perfect bit and pieces when they are assembled that way.
 
I wouldn't worry about it. As MET said, the functioning surfaces are perfect. I strongly suspect that the piston is precisely the way it came from the factory. The pits you show are in a non-critical area (no finish-machining was done there, even), won't affect the operation or longevity of the piston, and probably were passed by the QC inspection as adequate for use. Most eastern-block firearms I've taken apart had areas where, if it didn't show & wasn't critical, it wasn't finished or polished. I strongly suspect that's what you've got.

Shoot it & enjoy it!
 
Don't sweat it. Rib a nice coat of heavier oil on the part the contacts the cylinder, and the rod. Go and enjoy it. If you're not happy with that, I could chuck it in a lathe and sand it a little for you on that surface...
 
Haha op, I freaked out like you when I had a tiny bit of pitting so I went and bought a full parts kit. Needless to stay the original piston is running just fine.

I suspect in a cz the piston would have to be pretty far gone too actually affect performance
 
i had a piston worse looking then that. i soaked it nitro solvent and spent about 45 minutes with a brass brush scraping at it and it came out like new. i was positive it was pitting but it turned out it was carbon baked on top of more carbon. its a very hard area to clean and takes allot of effort to get it all off.

the person i bought my cz from fired corrosive through it and never cleaned it. the barrel was a write-off but the piston came out like new. keep trying to get it cleaner. it may be ok. good luck:cheers:
 
Drive er, till she brakes. my piston head has some pitting around the edges and the gun still runs flawless. Until it becomes so bad that the gas leaks by and it doesn't drive the piston hard enough I'm Gona keep on using it.
 
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