Good evening everyone-
Last Friday I got a chance to get my vz out for some shooting (first time out with this rifle, what a wonderful afternoon!) We put about 200 rounds through with no issues, over the space of a couple hours. When I began cleaning the rifle on Friday night, the piston was difficult to remove- it slid front to back ok, but wouldn't clear the gas tube when puled back and tilted up for removal. I though that was really strange (I've had it apart a couple times while waiting to get out shooting), and in order to get it out, I rotated the piston 180 degrees, then it lifted out just fine. After cleaning, the same situation arose while replacing the piston, it required 180 degree rotation in order to replace it. Has anyone ever experienced this? We were shooting outdoors, and it was 20-25 degrees or so outside that day (not sure if temperature would have had any effect on it). Thanks for any insight you may be able to provide.

Put the piston in a drills chuck and set it away (low speed). You should be easily able to see if the piston is bent or not. You might even be able to feel it as a vibration if you turn up the speed.

Is your vz a century built vz2008?   A properly built vz58 should not have any issues removing the piston.  Take some measurements and post them up

No, not a Century build, it's a D-Techniks, piston stamped USA. Ill be looking into it, and will let you all know the results once my work week finishes. Thanks for the input!

Are you the original owner to the rifle?

No, bought it on Armslist. Had 1 FTF out of 200, about round #50 (thinking magazine problem or single bullet problem. Put that magazine aside, we were having too much fun to test that out). There were no indications that anything was wrong until I went to clean, and had trouble getting the piston out. It came out of the gas tube just fine, but seemed to have developed a slight bow, so if I rotated it 180 degrees, it came out fine. Won't have a chance to do photos, measurements until Wed, but will let all know what I find out. I found Czech manufactured pistons on Gunbroker for $20, will probably go that route....

Just a heads up that...csa/czechpoint pistons are not part of the mandatory 922r compliance parts.  So that USA bent marked piston was probably changed out by original owner.  If I were you to be safe, I would directly order from czechpoint.  

OP -
Did your VZ come with a different hand guard? Or original beaver barf?

I bent my piston when installing an aftermarket handguard from FAB. The gas block was canted when I installed, and I did not notice. There was VERY tight tolerances... I needed the Dremel Genie's help once I couldn't remove the piston easily, and traced the problem back.

Good luck either way! Bonesteel has new for a good price.

Because we all know that Czech pistons are indestructible

If your Czechpoint CSA gas piston is labeled USA then its probably a CNC warrior piston. They make them for several of the other companies that sale them.  Just drop them an email or call they may replace it for cost of shipping. It never hurts to try. They were always friendly with me when I had a problem with one of their products.