75b Random Slide Lock Back

[Seth]

I recently acquired a used 75b that seems to not much care for Blazer 115grs. It randomly locks the slide back with rounds left in the mag with some regularity. I trimmed the slide stop back and tweaked the slide stop spring and I'm still getting a few.

Any ideas?

Seth

[19852]

I have been shooting the same CZ 75 for about 8 years now. My "go to" pistol for competition. It's slide stop has been trimmed and I load short with 124/125 gr. bullets. What you described still happens, infrequently, but it still happens. I blame my high grip and long thumbs. For me, it is most likely the second joint on my thumb that makes contact with the slide catch. Does it happen when you shoot strong hand only?

[Seth]

Yep. Just happens, Lead round in the mag shows a scratch on it though, so I may have to just trim the SS back more....

[eerw]

Seth..I trim it back pretty far.

you can take a lot of material off. a lot will depend on your OAL and the bullet profile especially if shooting 147 bullets

Edited June 3, 2009 by eerw

[smallshot13]

I had the same problem with a new 75B earlier this year. I finally diagnosed the problem down to the slide stop spring not providing sufficient pressure to keep the slide stop from jumping just enough to catch open. I tried replacing it with a new one sent from CZ USA (for free) but that did not work. After examining how the mechanism worked, I reformed the spring with a slight bend to provide more downward pressure on the slide stop. Problem immediately gone and has not returned. Caution, there are at least 3 different variations on the shape of the slide stop spring out there.

[eerw]

very cool..any chance you have a photo of the modified slide stop spring??

good info to have.

[Vlad]

When I had this problem I adjusted the mag feed lips as they were getting a bit loose and letting the top round ride to high. It fixed it for me.

[blind bat]

I tossed in a new slide stop spring and trimmed my slide stop back to look like eerw's. I still had at least one random lock back per match so I ended up bending the spring and taking some material off the and bottom of the slide stop where it hits the frame. That way it would sit lower and require more travel to lock back the slide. It hasn't been an issue for almost 500 rounds. Unfortunately, all those mods made the slide unlock with a fast reload. That's not great but definitely preferable to having the slide lock back randomly.

Out of curiosity what year way your CZ made?

[smallshot13]

very cool..any chance you have a photo of the modified slide stop spring??

good info to have.

I don't have a photo, but the mod is very slight. EERW, you are probably very familiar with the slide stop pic posts over at the CZ Forum. The one I have is just the straight version. On the muzzle forward end, it is held in by the small pin, and on the breach face end, there is a small 90 bend that fits into a hole in the frame. The mod I made was to induce a very slight downward curve in the middle of it, maybe 3/64" max. Since the spring is secured at each end, that induces more pressure on the flat on the slide stop. CZ sent me a spare. I will see if I can take a pic of that unmodified, then bend as I did the other one.