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Firearms and Gear => CZ Handguns => Topic started by: PappaWheelie on April 06, 2019, 02:53:28 PM
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Eat Crow and Humble Pie, PappaWheelie.
It was only due to coming across a czfirearms.us thread by charlestheforth about a possibly stiffer outer recoil spring (than the highest preload DPM outer) for my "Punching Above Weight" Invisible 15 Round RAMI that I actually shot a half magazine of my carry ammo, with Wifey assisting with location marking of the chosen 7 rounds in order to get an average.
The good news is that the Wolff Kimber Ultra spring was a clear improvement, dropping the average casing distance by 1.3 feet.
The even better news is that the 6(!) FTFs between my RAMI and my SP-10 Tactical's 12 "rechamberings" showed a strong tendency for a leg of the Xtreme Defender's flat cruciform nose to get hung up on the bottom of the feed ramps of both pistols. I.e., good thing to know before you actually need flawless reliability! It seems the spaces between the cruciform's legs provide opportunity for the nose of the bullet to advance without the associated elevation that a circular face dictates.
https://czfirearms.us/index.php?topic=102671.msg803459#msg803459 (https://czfirearms.us/index.php?topic=102671.msg803459#msg803459)
Maybe I'm part Scotch, but I had not yet used my more costly carry ammo for "mere target practice." I'm actually surprised in retrospect that my first trials with the DPM springpack and the Xtreme Defender ammo (5 shots, so 4 rechamberings) didn't expose the problem. http://www.czforum.com/forum/index.php?topic=5506.msg23284#msg23284 (http://www.czforum.com/forum/index.php?topic=5506.msg23284#msg23284)
At any rate, bottom line, I concur with all those who have heretofore advocated doing firing range practice with your latest carry ammo, if you make any change, to verify reliability. Duh...
I've alerted both Underwood Ammo and Lehigh Defense to my experience with their flat cruciform nose bullets and 9mm CZ feed ramp lengths.
In the meantime, in that I have a number of boxes of this ammo, and only need two "chamber only" rounds, I'll experiment with tapering the cruciform legs at various angles to see if a conical angle and intersection diameter combination that would reliably "cam" the nose up onto the ramp can be found.
Thanks again, charlestheforth!
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UPDATE:The limp-wristing risk behind this post can be ameliorated by conicalization of Xtreme Defender bullet noses.
https://czfirearms.us/index.php?topic=103666.msg804887#msg804887 (https://czfirearms.us/index.php?topic=103666.msg804887#msg804887)
05/02/2019 UPDATE: https://czfirearms.us/index.php?topic=103666.msg807725#msg807725