Cz 85 Combat - 9mm Production Gun

[jkushner1]

Spontaneous slide lock activation - mid satge IPSC

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Need Advice:

Own an 85 Combat in 9mm for IPSC. Anyway, for over a year I have been running a 12lb Wolff CZ 75 B spring and this gun runs and runs and runs, never any problems. At yesterday's IPSC match on four or five ocassions including a weakhand string during a classifier, the slide just decided to lock open (the slide lock lever engaged spontaneously) with anywhere from 3-8 rounds in the mag. The only thing Ive changed recently since the problem developed, are some new CZ Factory 16rd (not 15 OFM Mecgars) bought from CDNN (only loading ten to start). Same ammo, same grip, etc. I cant figure this one out since the mag follower has 3-8 bullets laying between it and slide lock position. I am running 147 grain bullets that are slightly longer than std. - maybe theyre hitting the internal portion of the slide lock upwards as bullets are feeding, I've already had to file the internal knob/head portion that engages the slide at slide lock, as it was too long and was shaving brass from the bullets as they fed into the chamber from the mag during cycling ??

Any thoughts greatly appreciated.

Jon

[Matthew_Mink]

I betcha the longer bullets are hitting the slide stop, even though you have filed it down some. On my CZ's for competition use, I take considerable metal off of the slide stop to the point where it will just engage using the new 16rd mags. I also load the bullets a little shorter than normal, to 1.100". I've never had the slide lock engage doing this.

The other thing that may be happening is you are just hitting it with your hand.

[Flexmoney]

Makes sense that the bullets could be hitting it. Especially with the different mags...they might be presenting the round at a different angle than your other mags.

[Zak Smith]

I had this same problem with one of my CZ's. Not wanting to mess with it, I sent it back to CZ-USA. He claims to have replaced the slidelock lever spring, and it works OK now.

[jkushner1]

Thanks Gents:

Matt - It also happened on some strong/weak strings of a classifier, so I dont think I'm hitting it with my hand. I think the new 16 rounders may present the bullet for the slide to take at a slightly different angle as mentioned above. The material I took off was probably .150" to .250" and the bullet shaving problem stopped with my Mecgars and older CZ 15 round mags. SO I should probably take more off eyeballing the follower/slide lock contact point a remove more material but leave enough for the follower to still just barely contact and engage the slide lock. Check my logic here.

Thanks,

Jon

[Matthew_Mink]

Jon, that sounds about right. I have found that if I get to where the slide lock misses the bullets 100% of the time, the 16rd mags will lock the slide, but the 15's will not. My solution to that problem was to buy more 16's.