Hello all, and Joe, thank you for your interest. Having this problem has made me learn a lot about the CZ in general. What I did the other day, was take all my full size mags, load them to capacity, and let them sit to take a set. Yes, springs do find a set. I have proven this many times over. I also think this frame is on the out edge of acceptable, which may explain why this kit works perfectly on my SP-01, but struggles a bit on my 75B.
Anyway, I made 2 minor adjustments before the range visit yesterday. One is as I said, I left the mags to let the springs set, and second ( which someone said earlier) I swapped out the slide stop for one that had a slightly smaller diameter shaft. I have found variations in shaft diameter of .0015. I used the "thinnest" one, to assure that the slide stop spring would allow the slide stop to fully disengage when I rack the slide back. Also, it introduces a hair more "slop" or clearance for the assembly. Remember, I believe this frame is a victim of tolerance stack.
Yesterday, I used this all on kit #2, which failed the same as kit #3 when installed on my 75. I used kit 2, because after the rear sight fell off ( and my subsequent repair) I converted this kit to a dot sight, using CGW Docter mount, and a Vortex Venom sight. So I needed to sight it in anyway.
285 rounds, and after initial sighting ( mags loaded to 3 for groups), I loaded all mags to 10. It only failed to feed when racking the slide 2x, which is an improvement. If I can get kit 3 to do the same, I will say I am on my way to fixing it.
Joe, I will indeed do the polish of the ramp. The only area that concerns me is the lower portion of the chamber, directly above the ramp. Can I smooth this edge? Not to remove a lot of metal, just to knock down the sharp 90 degree corner?
One more interesting point, is I was able to run CCI SV and Norma Tacs without any cycling issues at all. It was in the high 40s, so I am sure that helped. Either the CCI SV is VERY inconsistent, or the gun is picky, and will only eat SV when it wants?
All in all, I would prefer to run CCI SV and Norma Tac, as I have a fair amount of this ammo, and find it pretty good accuracy wise. I think the Norma is a touch hotter than the SV, but I have no chrono results to back that. I base my statement on the report?
Rich