The Original CZ Forum
GENERAL => Ammunition, questions, and handloading techniques => Topic started by: Stealth01 on January 19, 2023, 07:53:34 PM
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During my rotation of guns to the range I selected my CZC A01-LD. During the shoot of 100 rounds I experienced a significant number of FTRBs (Failure To Return Battery), approximately 10% of the rounds sorry, I wasn’t counting, just irritated! When I arrived home I decided to do a “plunk” test with the ammo I was using. Fifty percent of the rounds exhibited “some protrusion” from the chamber while ~10% of the 50% exhibited “significant” protrusion from the chamber (that would line up with the FTRBs I experienced). Hmmm, COL issues?? So I measured the population of failed rounds… All but 2 measured 1.160”… What the hell?? Now, here is the kicker, 100% of the offending rounds PASSED the plunk test using a CZ Shadow 2 Orange barrel! I had heard that CZC chambers were “tight” but I was surprised by these results, especially the fact that all of the rounds passed in a CZ barrel!
(https://i.imgur.com/SSAKJeo.jpg)
No protrusion.
(https://i.imgur.com/XrAxWud.jpg)
Some protrusion.
(https://i.imgur.com/8x8qx8S.jpg)
Significant protrusion.
Again, all of these rounds PASSED the plunk test using a CZ Shadow 2 Orange barrel… Just food for thought…
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I have never had that happen with my A01 - LD. But i only have 300 rounds or so through it
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What type/weight bullets are you running? Coated bullets tend to need shorter OAL's than plated/FMJ.
Sent from my SM-G970U using Tapatalk
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My 2 Bull Shadows have a much tighter chamber than my other CZs. I do all my plunk testing with my CZC Bull Simi compact as it for sure has the shortest lead. I only really have issues when I load 147s but ….I shoot that size a bunch. What size, shape, and brand are you shooting?
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Welcome to the Ammo Forum !
• Let's start with where the ammo came from. Is it "factory" or reloads. If "reloads", then was it your product or bought at the range ?
• In the interim you can read the appropriate section in the Stickies at the top of the forum.
• Question: Did you save any of the offending rounds for detailed measurements ?
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The CZC barrels, in my limited experience, have tighter chambers that the Czech made barrels.
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The article that Wobbly referenced is here: https://czfirearms.us/index.php?topic=114239.msg888899#msg888899
It is bullet dependent. Not all bullets are created with the same profile/shape nor are all barrels cut with the same freebore/leade.
Cheers,
Toby