light strikes FTF- odyssey of a kadet

[joerchi69]

I don't think std velocity 22 ammo will have enough power to move the slide all the way to the rear to feed the next round from the mag, or lock back with those extra power springs. I could be wrong.

If you shoot a steady diet of mini mags, or the very high velocity stuff like velocitors...maybe.

I think the right way to go is to put in the 17 lb spring, and shoot quality std velocity ammo, and go from there.

Testing the 22 lb hs went quite well. And as expexted by painter.
In 200 rds of CCI standard velocity 7 times the slide did not lock back on the last round. 4 times the next round wasn´t feeded. But no missfire at all. Didnt clean the gun to go on with
200 rds of CCI Select. Everything worked fine. Blazer should work similar, i suppose. But leaving more dirt.

first row     CCI sv        22lb FP3 unmod
second row CCI Select  22lb FP3 unmod



tending to modifiy the FP a little ..

[joerchi69]

todays dents

first row     CCI Select  22lb FP3 unmod
second row CCI sv        22lb FP3 unmod

compared to older brass dents (Sept.15)

third          Blazer  20 lb mod FP
fourth        CCI sv  20 lb mod FP

[joerchi69]

todays dents

first row     CCI Select  22lb FP3 unmod
second row CCI sv        22lb FP3 unmod

compared to other older brass dents, mod FP 20 lb + spacer 1,6mm (Sept.13)

row 3-5 CCI Select
row 6 Blazer



I would like to shape the FP close to that. And test the hammersprings down from 22 lb to 17 lbs. Hopefully there is
 one working well with the sv CCI ammo.

[painter]

Joe, the best recommendation I can make to you, at this point, is to slow down and only make one change at a time. If you make multiple changes you'll never really discover what is doing what.

That said, if it were me, I'd put a 17lb spring and a re-profiled firing pin in the gun, and go from there. At that point, make one change at a time.

Good luck!

[joerchi69]

Installing the 17 lb hammer spring/main spring. Out of the reduced power hammer spring pack from wolff.
26506    CZ75/AT84/P9 9MM, RP HAMMER SPRING PAK
https://www.gunsprings.com/CZ/75%20Series/cID1/mID16/dID91#838

[joerchi69]

Was shooting the kadet with the 17 lb hammer spring. In combination with the unmodified FP3. One handed.
100 CCI select worked 100 %.
  50  CCi sv not. Light strikes 4 times. And the slide closed on the last rd 2 times.
100 CCI Blazer had 5 light strikes. The slide stayed open on the last round always.

Maybe with the light strikes the slide is sometimes not cycling back in batterie completely with the CCI sv? But why is it happen with the stronger Blazers too ? And never with the CCI Select. Maybe the brass is harder on the Blazers ? And the priming compound more sensitive on the CCI Select ?

If i would shoot the Kadet only two handed i would be fine and stay with the stronger, cleaner and always working CCI select. But i prefere the soft shooting CCI sv especially when training and compete one handed. The gun jumps less, the muscles work less, the arm stays a longer time more stable to aim without shaking. I seem to get more precise target hits out of the CCI sv.


The foto shows
on the first row light strike unfired manual ejected rounds CCI sv
on the second row to compare fired cases CCI sv
on the third row light strike unfired manual ejected Blazer rounds
on the fourth row to compare fired cases of Blazer ammo



same motive from the left side

Bullets
Cases
Bullets
Cases

[painter]

Try the modified firing pin.

One thing at a time.

[joerchi69]

Some lightstrikes again today with CCI sv. And the 17lb hammer spring. So i started to modifiy the FP3 back at home. The new dent area on a used case besides the original is seen on the pic. Will test it next week. To get the CCI sv running flawless i will also try maybe a reduced recoil spring additional on the next step.

[joerchi69]

On the range a member of the club showed me his original Kadet to discuss the loading errors.
It is a older model with the firing pin with the round tip, metall recoil spring guide rod and hard plastic grips. He bought the complete gun some months ago when it was nearly unused. Today we had a closer look to it. The round is hitting the feeding ramp out of the center axis to the left. The magazine and follower also is pointed to the left when inserted in the frame (and looking on it without the slide). Same with another mag. We also found lead chips around. Happy! it is not metal.

When examining for sluggishness and stress marks we found the FP stop broken twice. No probs with light strikes.



We figured out that maybe; the hammer tension when get cocked by the slide shoved the FP stop up over the level of the slide. When rushing back it hit repeatedly the upper frame and broke on the weakest spots.

[painter]

Some lightstrikes again today with CCI sv. And the 17lb hammer spring. So i started to modifiy the FP3 back at home. The new dent area on a used case besides the original is seen on the pic. Will test it next week. To get the CCI sv running flawless i will also try maybe a reduced recoil spring additional on the next step.

That firing pin imprint looks excellent, Joe!

[joerchi69]

Due to the club`s yearly tournament i had to slow down the kadet project a little the last weeks. But this thursday i went to the range to test the kadets behavior with increasing the hammer spring force. Starting as recomended from the 17 lb hs i escalated pound by pound over 18, 19, 20 and finally 22 lb. Was the plan. Using the above shown FP3 and the CCI sv ammo which i would like to run my CZ with permanently and reliably. The rails where repeatedly oiled with a thin ballistol ceramic oil (CunCer).
To have some half-decent experimental set-up i thougt to shoot 100 rounds per spring. The 17 lb gave a lot of light strikes (12) which got less with the 18 lb hs. But here startet the slide not to stay open on the last rd occasionally. With the 19 lb hs just 3 light strikes, 3 slide isues and new - missing rounds (2) in the chamber. The have not been stripped from the mag.
Jumping to the 22 lb spring i had no light strikes, 3 slide isues, 3 missing rounds and two stove pipe surprises.
So the standard ammo was not strong enough for the strong hammer spring in combination with the regular recoil spring.
To reduce the amount of overall spring power which the ammo and the slide has to move, i started cutting down the recoil spring 3 windings and used the 20 lb hs. No light strikes but a slide closing one time on the last round, 2 missing rds and a stove pipe. Cuted down another 2 windings with the result of having a light strike, a slide, a missing rd and a stove pipe on 50 rds. With the shooting time running out i combined the 5 windings shorter recoil spring with the 22 lb hs with 50 rds - 5 light strikes, but nothing else.
As stated by painter the sv ammo has not enough power to move the slide all the way to the rear to feed the next round from the mag, or lock back with those extra power springs.
Back home in a sort of displacement activity, i completely cleaned, degreased and dryed the gun with pressurized air to prepare it for the treatment with an new and other sort of lubricant. A solid, dry and residue free ceramic lubricant (Fluna). Have a original length replacement recoil spring in stock too.

[joerchi69]

Today i tryed another time combinations of springs and firing pins. CCI sv in 50 cartridges paper boxes. 450 shots.
I ended up with FP3 (with a little reduced hit area), the original 20 lb hammer spring of the SP-01 Shadow1 and a reduced Kadet recoil spring. Minus 6 coils. In that combo i only had to accept that the slide did not open on the last round. But no light strikes. To get the slide lock back i could try to cut of annother winding or try that fix described by Joe 75 plus.
https://czfirearms.us/index.php?topic=22581.0

Before cutting of coil number 6 from the recoil spring i had the same slide issues and 3 times an empty chamber because the rd was not stripped down from the mag. With the 19 lb hammer spring in the grip i still has 3 light strikes on a box of 50. With the 18 lb hs 3 light strikes and a slide issue.

The Fluna tec gun coating stayed quite good on the rails, no relubing was needed. Cleaning the gun at home showed less powder residue in some areas. I credit that to the Fluna too. Or the CCI sv ammo is cleaner now.
 

[joerchi69]

Pic and delineantion to post above

testing CCI sv,Top down

First row: FP2, 17 lb hs, rec.s -5 coils. Every second shot a light strike.
2 row:     FP1, 17 lb hs, rec.s -5 c. 10 light strikes in 35 shots.
3 row:     FP3, 17 lb hs, rec.s -5 c. 2 light strikes on 50.
4 row:     FP3, 17 lb hs, rec.s original length, 3 light strikes, 3 slides, 1 stove pipe
"5 row":   FP3, 18 lb hs, rec.s orig. , 2 light strikes, 2 slides, 7 missing rds in chamber - not stripped from mag
6 row:     FP3, 18 lb hs, rec.s -5 coils, 3 light strikes, 1 slide,
7 row:     FP3, 19 lb hs, rec.s -5, 3 light strikes,
"8 row":     FP3, 20 lb hs orig., rec.s -5, no light strikes, 5 slides, 3 missing rds,
"9 row":     FP3, 20 lb hs orig., rec.s -6, no light strikes, 6 slides, no missing rds,

[joerchi69]

Tested the combo who worked at the end of the last range day. CCI standard velocity, the lightly reshaped FP3, original hammer spring and cut down (-6 coils) recoil spring. In the first 200 shots only one light strike and one stove pipe. With the fifth 50 cartridges paper box i got 4 light strikes and one time the slide not locking back on the last round. After cleaning the chamber and the contact areas from slide to barrel - zero malfunctions for another 100 rounds.




new and old layout

[painter]

All the CCI SV I have looks similar to the box on the right. Instead of saying 35EU, it says 0035. I wonder if they make it differently for Europe?

Your last set of results are approximately what I get, but I can use a lighter hammer spring and an unmodified recoil spring. I do have a lighter firing pin spring that I got when CGW had them available. The light hits are caused by the wax lube getting between the rim and the barrel face. I might be able to go a few more rounds before a light hit, and I rarely get stove pipes. I will occasionally have a failure to strip off the next round in the mag, but that's just a weak round.

The only other thing I can suggest is to try a weaker firing pin spring, not shorter, weaker. Some have used the spring from a ball point pen.

Unless you want to try a different brand of ammo to see if it will go longer, or perform with lighter springs, I think you've gotten as close as you're going to get.