CZ858 stuck piston assembley

[iseestars]

I used the gun without fail, it shot 230 rounds last time I shot it. Days later as I was showing the gun, I noticed the piston was siezed in the forward position. I removed the piston to closer examine it. It looked good- but I carefully spun some 400gr. sandpaper around it, to eliminated any possible burrs causing interferance- But when I re-installed the piston it would not slide into its bore using spring pressure- or manually:

After alot more investigating the problem was found to be in the return spring cavitiy. There is a small piece- maybe a piston rod guide, that is able to move. It was causing the piston rod to bind- not a problem on the piston end. Maybe I moved it while cleaning...?

I just centered the "guide" and all is good now.

I am not sure how common this is, but I thought its worth sharing.

 

[Curtton]

There is a small piece- maybe a piston rod guide, that is able to move. It was causing the piston rod to bind- not a problem on the piston end. Maybe I moved it while cleaning...?

mine has no small piece , does the rod move freely without this piece?

 

[DMcFaul]

I have to look, I don't think I do either.

Not to sound like a jerk.. but are you sure this 'guide' is supposed to be there and not a foreign object?

 

[Stevo]

I believe he's referring to the piston stop, both of my rifles have it. I didn't realize it was movable.

 

[DMcFaul]

Ahhh... I'm going to have to take mine and see what it takes to knock that out of place. Mine has never moved.

 

[iseestars]

I think Stevo is right. How or what keeps the stop in place .My friend has the same gun- his has back and forth play, but nothing more. I am wondering if this should be a warranty issue.

 

[H Wally]

I've never noticed that - perhaps put a drip or two of JB weld in there then put it in place and make sure it doesn't move until dry.