Failure to fire jam perhaps with 115 grain loads

[Hemiscorpius lepturus]

first glance says that extractor looks fine, how well does it pivot, is there any binding?

I know my 20rd mags had 30rd springs in them, resulting in too much spring force when the mag was loaded, had to cut them to get equivalent force to the 30rd mags, it could be possible the 10rd mags are iffy, how many rounds are in the mag when it jams?

As for 115gr not having enough energy, that is crap, this is a blowback gun and even weak sauce 115gr like magtech seems to work fine (at least in mine). 115gr does NOT work in my "duty pistols" which are sprung for 115+p or NATO rounds, they will fire but stovepipe or not fully extract, as a browning action is much more sensitive to energy, too little and you have extraction problems, too much and the slide slams back with too much recoil and poor reliability.

[Trooper894]

Have you done a bolt tear down and thorough cleaning of the extractor and recess. Pay particular attention to reassembly, spring condition and parts orientation. Here is a link to a decent video showing disassembly/reassembly:
https://www.youtube.com/watch?v=zmokE2mmwOA
The rub/scuff mark on the rim of the loaded round appears normal for the extractor attempting to snap over the rim.
Take a good look at the ejector to make sure the tip hasn't been damaged or broken off.
I agree with what others have said, in that the Scorpion's blowback action should function with ANY factory in spec ammo. Mine thrive on Wolf steel cased ammo, which tends to feel a little on the weak side.

[Vincent_Diesel]

Thanks all for the help.

Bit of an update. After a very thorough cleaning and a complete bolt disassembly, I went back to the range. I also used a different magazine (newer CZ black window magazines). Good news is that out of 100 rounds I managed to get down to 2 failures, same 115 grain range ammo. Much improved, but still looking for zero malfunctions which I know this PCC is capable of. This time it wasn’t a failure to extract (it seems to be extracting fine now after cleaning) but looked more like failure to fire. Bullet looked to be seated in the barrel when I peeked inside chamber.

When I got home I did another complete bolt disassembly and I had noticed something unusual, like an extra part. The manual didn’t call for, or even listed this as a part. It looks like a washer that slides in before the main recoil spring. A washer that in my guess, looks like it is intended to create more spring tension. Anybody know what this is? My brain is telling me, this is what may be causing 115 grain loads to possibly not have enough energy to fully blow back the bolt causing my jams. Was it a post add on part either from CZ or from the original owner?



 

[Vincent_Diesel]

Have you done a bolt tear down and thorough cleaning of the extractor and recess. Pay particular attention to reassembly, spring condition and parts orientation. Here is a link to a decent video showing disassembly/reassembly:
https://www.youtube.com/watch?v=zmokE2mmwOA
The rub/scuff mark on the rim of the loaded round appears normal for the extractor attempting to snap over the rim.
Take a good look at the ejector to make sure the tip hasn't been damaged or broken off.
I agree with what others have said, in that the Scorpion's blowback action should function with ANY factory in spec ammo. Mine thrive on Wolf steel cased ammo, which tends to feel a little on the weak side.

By the way this video is amazing!

[Trooper894]

I'll be honest with you, I have never had a need to disassemble my recoil spring /guide rod assembly, but you are correct, that part does not appear on the parts diagram. I believe your hunch that it was added to provide additional tension to the recoil spring may be the source of your failure to extract the lighter bullet ammo problem. Was the "spacer" on the guide rod, inside the bolt, in front of the recoil spring? This video animation of the complete disassembly and reassembly of the Scorpion and sub-assemblies doesn't show that spacer either. https://www.youtube.com/watch?v=u_bsC3ppfwo

[Vincent_Diesel]

Yes. Precisely, on the guide rod, inside the bolt in front of the recoil spring. Have removed the anomaly and will hit the range this week.

[Vincent_Diesel]

Just want to say thank you to those who helped me figure this out. Glad to say that after my last range visit, I report Zero malfunctions, after 100 rounds. It was the darn spacer that somebody decided to modify.

What I've learned:
• Don't mess with internals unless you really know what you are doing
• When buying used, buy as close to stock form, know what you are getting in to
• So important to properly maintain your gun, includes knowing how to tear it down and properly put it back together again

Thanks again all!

[Hemiscorpius lepturus]

I would assume that is an intentional modification from a prior owner who liked to shoot +p or +p+ ammo or suppressed and needed some extra spring pressure to mitigate the slam-back of the extra recoil, I shoot mostly NATO spec ammo, but have a very effective muzzle brake so it feels like a .22

[CZShooterP01]

I’ll agree with everyone saying that spacer is not a normal, factory part. FWIW, on these blowback pcc’s, dirty extractors will cause failures to extract. I recently tore my own EVO bolt apart after about 2,500 rounds and scraped out a bunch of greasy gunk from on and around the claw. I had been having FTE every 2 or three rounds. After cleaning, just dumped 200 flawless rounds through it. Seemed to remedy the problem.