My CZ is driving me nuts

[Vlad]

Hi guys,

I started a thread in the spings forum earliers thinking that was the issue, however I no longer think so. Here is what happens.

My CZ75B 9mm gets some killer jams. The jam is a empty case stuck between the slide and the barrel mostly lined up with the chamber and with a new round moving up the feed ramp and stuck under the empty case and partially still in the mag. This is a harsh one as I have to rip out the mag (which is not easy as the half stuck round at the top wants to hold it in) then rack the slide to allow the case to fall out the ejection port and shake the gun to get the round stuck on the feed ramp to fall out the magwell. This happens with all mags.

Now, I first assumed that the slide moves the next round forward when chambering and that the empty case gets bumped of the extractor by the nose of the new round. I replaced the mag springs with Wolff +10% and tightened up the feed lips a bit. This does seem to mostly fix the round moving forward under the slide problem when cycling the gun by hand. After 300 rounds with no problems I thought I fixed it.

Then yesterday I shot a local match where my gun worked great for 3 stages and then on the fourth I had 6 jams. After wards took my gun apart and cleaned up the inside if the slide, the extractor, and barrel, and the gun worked great for the last 2 stages.

The extractor was replaced recently, and it is in good shape. The extractor spring is a Wolff extra power one and if I slip a case under it it holds it VERY well. A budy suggested that maybe my mag release is forcing the mag to high. That might make sense if it was happening all the time, but I doubt that I am forcing the mags harder in the gun on stage then on all the others. It does however seem that if I clean my gun the problem goes away for a short time. So I took a long hard look last time I cleaned it and I can't tell what makes it jam. Sure there is some soot on the extractor, but no buildup. The feed ramp is dirty but I don't see how that matters. The rest of the gun looks pretty clean. In fact if was spotless when I started the match yestarday and the failures started after about 80 rounds. Then gn was just not that dirty after 80 rounds. I use CLP and SlideGlide to keep my gun going, in case anyone thinks that matters.

Lastly my springs are 12lb recoil and 16lb hammer. I have no idea if that is part of the problem or not. The bottom of the slide is beveled where it runs over the next round, so the fix that Ron Ackeny had for a similar problem with his gun, may not apply to mine.

Folks, I'm at my wits end. If you have any ideas, suggestions and wild ass guesses I would love to hear them.

Vlad

[RogerT]

Hi Vlad.

I've been shooting my new CZ75B since april this year, approx 5' rounds with one or two "hickups" due to my use of old magazines with bad springs, so I really can't relate to your problem.

However, I had a lot of extraction related problems with my earlier CZ, a CZ85B. One thing I think you could try is a lighter recoilspring (standard, perhaps) together with a standard extractor spring.

My reasoning goes like this: The extractor holds the empty case so well and in combination with a stronger recoil spring the slide travels slower rearwards so that the ejector does not do it's job and hurl the empty out of the slide.

What do you think?

[rhino]

Vlad ... the problem you mention is not uncommon with 1911s, and diagnosing the cause is often troublesome (as you know!).

If you have not tried it yet, I would have a good smith put a little bevel on your EJECTOR. The problem is that the empty case is not getting clear of the gun fast enough, and may actually be "bouncing" back into the works of the gun instead of clearing the ejection port properly.

Altering the angle of the ejector properly can cause the empty to be ejected more to the side and will thus cause it to exit the port more quickly. This is exactly what was happening with my Springfield Armory 1911A1 Loaded .45 years ago, and my FLG cured with 30 seconds and a file as soon as he realized what the real problem was.

[revchuck]

Vlad - How about returning it to stock configuration and starting over? If it runs perfectly stock, then you might be able to isolate the problem easier by swapping springs in and out and shooting.

FWIW, my 75B in 9x19 is bone stock with the exception of a Wolff 14 lb. recoil spring and Meprolight sights. I've had three (count 'em!) jams since I bought it new, and they were ammo-related. It's got about 7 K rounds through it so far.

[Matthew_Mink]

vlad, tell me your ammo specs. I had a few of those same type of jams early on, but I have it whipped. Stronger mag springs, stronger extractor spring, shortened the ammo OAL, and make sure the space behind the extractor is clean.

[Vlad]

Roger, the recoil springs is already 2lb lower then stock. I could go even lower I suppose.

Rhino, I see what you are saying but the case seems to be perfectly horizontal, and just caught between the barrel hood and breach face. In fact I even wonder if it ever touches the ejector at all, either by never getting there, or maybe it gets pushed higher up the breach face and missing it completly. I have to see if that is possible with an empty and no barrel.

Revchuck, you are probably right. I should put in a 14lb recoil spring and see what happens, though I can only imagine it getting worse. Who knows .. Its something I can try.

M. Mink, I'm tried various combinations. I'm using Tightgroup with 3.3, 3.2, and 3.1 grains and loads as short as 1.100 and as long as 1.300 all with 147gr FMJ (Zero). However now I'm not sure if I actually did try it with the very sort (1.1) loads. I know I started with that length but now I don't remember if any of the loads I tried while trying to figure it out where of that short vintage. Something I can try. I already have stiff extractor spring and extra power mag springs. I did check teh extractor after the last failure and it was reasonably clean, and I did take it out of that gun to make sure that was no gunk behind it.

Thank you all. Keep the ideas comming so I can try various things and see if I can figure it out. I wish there where and FLG's around where I live. Right now there seem to be none, or at least none which anyone would recommend.

Vlad

[Matthew_Mink]

Your load is similar to mine. I am loading at 1.120 or so with no problems. When I loaded longer I had the same problem you did. You might think about going back to the stock recoil spring.

[revchuck]

Vlad - It turns out I accidentally fibbed when I said the gun was bone stock. The gun is, but I have the extra power Wolff springs in the mags.

The OAL might be a problem. I load 125 grain Zero JHPs to 1.14", hardball to 1.15", and LRNs to 1.16". Factory ammo is usually about 1.15" If you have your ammo loaded long, and the bottom of the slide drags the top round in the mag forward, it might be just enough to cause the jams.

Matthew Mink, you one smart fella!

[MoNsTeR]

Ditch the extra-power extractor spring.

[Vlad]

Ditch the extra-power extractor spring.

I could but why do you think thats a problem?

Vlad

[Flexmoney]

Cause your gun doesn't run.

Don't worry about the "why" for now. Trouble-shoot and isolate the problem. Once you have done that, you can figure out "why".

Ditch EVERYTHING that isn't stock. See if it runs. If so, re-introduce the non-stock parts one at a time...testing after each.

I'd forget about the reloaded ammo for a while too. Get to Walmart and get some Winchester 115FMJ's in the val-u-paks. Everything should run with them.

[Vlad]

Well, I'll try some or all of the ideas listed. The problem is that the gun may run for hundreds of rounds and then fail twice per mag for 6 mags in a row. I'm not sure how many rounds of ammo I need to shoot to call every change "good". Given the possible combinations I would rather first figure out what the problem is and what makes the failure happen. Otherwise I could be swaping parts for a year.

One thing I noticed while tinkering tonite is that the empty case can move up the breach face far enough to completly clear the ejector. This would very much result in the jam I'm seeing as the round would be carried back forward and jam up against the barrel hood and the round under it. The questions however then becomes why would the case migrate up. I think I'll try a normal extractor spring and shorter round first. It seems to be less pressure on the case when in the elevated position then in its normal position. I'm guessing that the longer rounds push the empty case which is happy to follow he path of least resistance away from the strong extractor spring.

I'll try that first and then if it all fails, I'll go back to stock everything and start the slow painfull process of making one change at the time.

Thank you all for all the ideas.

Vlad

[revchuck]

Flexmoney wrote:

I'd forget about the reloaded ammo for a while too. Get to Walmart and get some Winchester 115FMJ's in the val-u-paks. Everything should run with them.

<<sound of LOUD buzzer>>

A couple of years ago there was a lengthy thread on the CZ forum about CZ-75Bs and Wally World White Box ammo. Apparently there is a dimensional mis-match between the cheap ammo's rims and the extractors on 75Bs. When all other decent ammo will run in a CZ, the WWWB will occasionally make them choke.

I don't understand it. It ran okay through mine, and the brass works fine in my handloads, but too many shooters reported problems with it to trust it in a CZ. Just FYI.

Get some American Eagle hardball. That will run in anything.

[Eye Cutter]

hey vlad, my buddy had those kinds of jams with his 85B. We changed to an extra power extractor spring and it went away for a few hundred rounds.

Then he had premature slide locks and double feeds again. I was thinking that he was inadvertantly hitting the slide with his thumb which slowed it down causing the fired case to get caught in the slide hood. We even emailed Mike of CZ-USA (we're here in Asia) and he said to check the spring holding the right hand slide stop lever as a loose spring will cause the lever to flip up and open the slide.

Regarding ammo, Milan Trkulja of CZ-UB recommended we use factory S&B ammo or reloads set to 1.160in.

My brother's 75B loads his ammo to a short 1.060in and he has not experienced any problems with that length ammo. I've been using 1.142in since I started in production division last year and I've been happy with that length setting.

hope you resolve your problem soon and keep us informed as it sure ruins a good shooting day when your pistol doesn't run 100%!

[jdt]

Hey Vlad- I would make sure that you found all of the springs that landed in the stones when you disassembled on Sun.

[Vlad]

LOL. Well I did find them all, and if you are the guy the help me find them I much appreciate it! Hey my emergency surgery did make sure that my gun ran for two more classifiers and worked well too. Heck, I'm a C shooter and I night have shot some a B scores that day so I can't complain.

I just loaded a batch of ammo at 1.11 and I took out all the Winchester brass, just making sure that the problem is not related to white box brass. I have a 4 stage practice match tonite, and we'll see.

Vlad

[rhino]

I still think that tuning the ejector will help, it can't hurt, and it will take only a couple of minutes.

[Vlad]

I still think that tuning the ejector will help, it can't hurt, and it will take only a couple of minutes.

You might well be right, the problem is that I know of no competent smiths around where I live and I have no idea what to do to it myself. Any hints what the said tunning would involve?

Vlad

[rhino]

Well ... it's essentially putting a bevel on the ejector to control which way the brass gets bumped. I know I am not capable of doing it myself without making a mess of the situation! Without an experienced hand on the project, I understand your dillemma!

[Sam]

Vlad, I have a CZ-75 too! I'm very happy with it. I was with Ron Ankeny the day he found the problem that was causing his to jam. It had a burr left by a machine tool on the bottom side of the slide. Once the burr was stoned away, no more jams. Quality control at the factory should have caught that one.

Since your CZ is jamming on an empty case, I suspect that the extractor is at least partially to blame. Take it out, clean it and the recess that houses it, and inspect it and it's spring for grit or damage. Either the extractor is letting go of the empty case, or "something" is knocking the empty case loose from the extractor.

That "something" may be the rim of the fired case catching on the case mouth of the round feeding up from the magazine. Most recently, this was happening to a friend with a 1911, who was using Winchester factory hardball (whitebox) . I was amazed, there was no taper at the case mouth what so ever! Make certain that you do have enough taper on the loaded rounds to keep the rim of the spent case from catching there. If there is no taper at all, a jam like you have described can indeed result. If the gun never jams on the last round, it may be hanging up on the top round in the mag, as I have described. I hope this helps. Please, let us know what you find.

[Little Bill]

Vlad-

I recently helped a friend through a similar series of malfunctions (appears as a intermittent Failure to Eject) with a different gun. We could not locate the problem at first: the ejector worked as it should, the extractor had plenty of tension, the mags were within spec, and the ammo was normal.

What we found was that the chamber was rough, and at the front of the chamber, by the case rim, it had gotten dirty/sticky. So occasionally, one of the fired pieces of brass would partially stick, and come out of the chamber very slow, causing it to not eject, and then the next loaded round would knock it off the extractor.

To rule something like that out, take a piece of YOUR fired brass, and drop it into the barrel until it headspaces. See how tight or sticky it is, and try to get it out with your fingers. On my friends gun, we had to push the brass the last 1/16", and then use a screwdriver to get it out. Once cleaned and polished, the brass fell in and fell out.

Just another idea.....

[Vlad]

Well, my slide seems to be burr free. I use a fairly heavy crimp with my Lee FCD. It was my theory as well that the round hit on the one under it. However now I have a new one, listed below.

The idea of the dirty chamber is certainly a good one. So I went after it with a vengence. I tried about 100 cases, and indeed many requiered serious force to push all the way in and even more to extract. I scrubed my barrel like a demon, using everything from CLP, to Sweets, and JB bore paste. And then I took a small felt wheel on my Dremel at very low speed and with some Flitz polished it for a bit, but not too much. While fresh rounds drop in and out just fine, and so do most empties, some empties always seemed to stick, until I noticed that it was the cases that where dirty with powder residue. We'll see if it makes a difference.

Last night, before I did the above, I shot a 4 stage practice match and the first stage was plagued with jams. Given that my brass wasn't going all that far, I took my gun apart, cleaned it again (it started the night clean anyway) And I replaced the spring with a 10lb spring. The next three stages worked just fine and my brass ejected about 6ft. away. BTW the load is very short about 1.11, trying to see if that helps.

I have no idea if the lighter spring fixed it, or if it is just in its normal mode where it works 5 stages and then it breaks on the 6th. Time will tell. I do however wonder if the problem was that the case doesnt alway hit the ejector and that a lighter spring allows for it to happen. My load is about 127PF using Tightgroup which seems to have a lot of impulse in the initial part of the recoil but little afterwards. I'm thinking that the combination of short impulse with powder residue blown on the cases and making them stick makes for not enough oompf. I noticed that I can cycle the slide slowly just so that the case doesn't hit the ejector but moves back far enough that on return it picks up a new round and tries to feed it. In slow motion I get a different failure with the case and new round kinda falling out, but a normal speed it might just result in what I am seeing.

Now the worry is that a 10lb might be too light and damage the frame. My logic is that if I am right and I'm short stroking that I don't see how I can batter the frame. Just in case I ordered a BT shockbuff and I'll see if it sees any wear on it with that 10lb spring. On the other hand I recall Duane saying that he runs a 12lb spring with major loads in his .45 with no damage ....

The experiments continue.

Vlad

[Little Bill]

Don't put a shock buff in it until you are SURE all of the bugs are worked out. Even then, I would not use one. They make many guns less reliable.

The 10lb recoil spring is giving the slide more rearward speed through extraction, and if the chamber was the problem, it would help rip the empties out.

Next time you go the range (with the clean chamber) try the gun with ALL of the stock parts / stock springs first. Then add parts that you consider important ONE at a time, testfiring for reliability with each one. (Good mag springs, X-power extractor spring, 10lb recoil spring, 17lb main spring, etc) When test firing, stick to ONE type or load of ammo.

Personally, I would bump the PF up to 135-140 for confronting large steel poppers, and for making the activating poppers fall a little faster. I don'think that you will notice a difference between 127 and 135 when the timer goes beep.

[RogerT]

Hi Vlad.

I would go easy on the way of light recoil springs, that trick cured my ejection problems on my CZ85 for a while until the slide cracked below the extractor.........

Using shock buffs is a MUST with light recoil springs! And by the way, the real cause of the ejection problems was a worn ejector (found it out later, when I bought a new CZ75B and compared the extractors. )

[Vlad]

As I said the springs worry me. Say, could you measure the length of your ejector and let me know what it is? That way I can compare it with mine and see if I need a new one? I would appreciate it is someone with a newers ejector (or gun) could check.

Vlad