CZ 75B Failure to Feed

[EndangeredSpecies]

Sorry this is so long.
Trying to capture the entire issue for troubleshooting.
I bought a new CZ 75B with the 10-rd magazines in November.
Took it apart, cleaned it out, lubed it up. A couple days later, ran 100rds Federal American Eagle 124gr FMJ (closest thing I could find to NATO rounds) through it.
It was hitting about 4" low at 25yds, dead-center left to right, and ran flawlessly.
Disassembled, cleaned, lapped the slide and feed ramp, cleaned, lubed, replaced the grips with LOK palm-swell bogies, replaced the front sight with 1mm green optic from CZ-Parts, received 2 Mec-Gar 10rd magazines.
2 weeks later, ran 100 more AE 124's through it. 1 failure-to-load when my off-hand thumb rode up above the plenty generous beavertail and lost a touch of flesh to the slide (user error). Other than that, ran flawlessly, and a joy to shoot.
Took it home, disassembled, cleaned and lubed.
~ 3 weeks later, ran another 100 rds AE 124's through it. Again, flawless. And, somehow, POI seems to be converging with POA (as CZ customer service advised it might, though I can't for the life of me figure out why.)

This time, before I got a chance to disassemble and clean it thoroughly, I brought my wife to the range. She mostly shot her GP100 to get comfortable, but together we ran 40 rounds through the 75B. Again, POI and POA got closer together (it's probably 1.5" low now), and it ran flawlessly.

I didn't get around to cleaning the guns until the following Saturday. Knowing I was going back to the range for 100rds on Monday, I didn't disassemble the CZ - just ran a patch of No9 down the bore, and followed with a few until they came out clean. (thoroughly cleaned the revolver.)

Monday came around, and the first 20 or so rounds were fine. Then I got a failure to feed. Finished the relay, but had a couple more where the slide didn't slide all the way forward into battery.
The next relay (of 48, 6 at a time, at 3 different ranges), probably 8 to 10 rounds didn't feed properly.
I finished the relay, apologized to the rangemaster, and took it home to see what's up.

Disassembled, thoroughly cleaned, lubed, reassembled. Loaded up the mags and just cycled the action through 40 rounds by hand (racking the slide, releasing, and racking again.) It must have jammed a dozen times.

Cartridge stops at the feed ramp, or part-way into the chamber.

I took it apart again, to see if I could see/feel anything hanging it up.
Rounds slip easily into the disassembled barrel.
Cycles like a dream with no ammo present.
Re-assembled.
Hand racking still produces about 25% failure to feed.

Read a bit. Disassembled, cleaned, and lubed the magazines.
Put a touch of synthetic grease on the slide rails.
Noticed it was hard to get a round into battery inside the slide. Blasted out the arched cutout that holds the case head; cleaned with a toothpick; lubed.
Seems better, but still not perfect. It does seem to get hung up more with the factory mags than the aftermarket ones, but the mec-gars are not completely without fault.

In most cases where it hasn't fed all the way, if I slam the slide forward with the heel of my hand it finishes the job and gets into battery. So it's trying, but seems to get jammed up somewhere along the way.

All ~ 440 rounds have been the same ammunition - again, the closest thing I could get to NATO-strength.
Ran solid for over 300, but now gets hung up to the point where I wouldn't use it in a defensive situation, and I hesitate to use it in matches.

Doing some more reading. Here are next steps I'm thinking of before my next trip to the range:

Disassemble, strip, lube with 0w-20 motor oil. (I've been using Tetra Gun Oil, except for the Redline synthetic grease on the slide rails.)
Disassemble and wax the magazines, and lube the springs and followers with a light wipe of 0w-20.

I thought the 75 was supposed to be pretty robust, and able to run in a lot of different conditions. Never expected this kind of trouble so early into its life. Also expected it to get better with break-in, not worse. Are my expectations too high?
My Springer XD45 has about 800 rounds through it, I've never cleaned the magazines, and it continues to run as flawlessly as it did on day 1.

Is this really likely to be a lube or magazine thing?
Has anyone seen similar problems on a late-model CA-compliant 75B?
Or am I looking at the probability of needing a new recoil spring? What weight?
Anything else I should consider?

[alp3367]

1 failure-to-load when my off-hand thumb rode up above the plenty generous beavertail and lost a touch of flesh to the slide (user error).

 Err...how did this happen? You're not wrapping your thumb around it are you?

 As to the FTFs it's hard to say. Sounds like it was working, but then "lapped the slide and feed ramp" and went downhill somewhere after that. Just about any 75 series should be extremely reliable. But it's hard to diagnose remotely. Are the FTFs always while firing? When loading? Both?

[crc4]

"lapped the slide and feed ramp"

Why?

[SI VIS PACEM PARRABELLUM]

Without quoting all or part of your extended post the VERY next thing you should do is stop grinding, filing, lapping anything. If this gun is new the next move you make should be to call CZ-USA and let them look at it under warranty. There is ZERO reason to be lapping anything on a 75B. These guns do not often exhibit what you describe.
By the way what is your overall shooting background?
 

[M1A4ME]

Factory recoil spring?  Or lighter.  Lots of people will go to a lighter recoil spring.  I've always run the factory spring and buy factory weight springs for spares (which I haven't yet used).

Magazine springs?  While I've not yet had to replace magazine springs a bullet nose diving into the feed ramp may be an indication of weak springs.  You're are pretty new so it's hard to believe the springs are weak already.  Does this happen with all your magazines?  Some people mark their magazines with numbers/paint so they can keep track of the ones they have issues with.  Another thing I've not had to do, but many people do it.

Waxing the inside and outside of the magazines has always seemed to help mine load easier (so they must feed out easier, too).  Also helps keep them cleaner and protest them from moisture.  That was a good idea and should be a benefit for your magazines.

Have you tried other brands of ammo?  My CZ's doen't seem to "like" Winchester 124 grain FMJ NATO ammo but it functions fine if I don't mind the ugly groups.

All cartridges of the same bullet weight aren't created equal.  The Winchester ammo (124 FMJ NATO) is supposed to be up around 1200 fps muzzle velocity.  What is the advertised velocity for the Federal you've been using?

I've only polished the feedramp on one CZ pistol, my Urban Gray P01.  It would do a nose into the feed ramp failure to feed every now and then and I could feel a spot (like a groove or scratch) that ran across the feed ramp from one side to the other.  Just one out of 11 or 12 CZ's.

Good luck with it.  They are great pistols.  Don't get burnt out on it already.  You know why the CZ is in my belt and not the M&P, SIG, Browning, XD/XDM, Glock,  FNS, etc?  Because the CZs shoot better groups than any of my other semi auto center fire pistols.

[EndangeredSpecies]

1 failure-to-load when my off-hand thumb rode up above the plenty generous beavertail and lost a touch of flesh to the slide (user error).

 Err...how did this happen? You're not wrapping your thumb around it are you?

 As to the FTFs it's hard to say. Sounds like it was working, but then "lapped the slide and feed ramp" and went downhill somewhere after that. Just about any 75 series should be extremely reliable. But it's hard to diagnose remotely. Are the FTFs always while firing? When loading? Both?

To #1: I had temporarily regressed back to my double-action revolver grip, and off-hand thumb was a little high. Not going to make that mistake again.

As for the FTF, they were first encountered during strings of shots during a relay. At first I didn't know what was going on, only that it didn't fire. After it happened a couple times, I noticed that after a shot, with more rounds in the magazine, the slide was not fully forward, and the round was not fully seated in the chamber.
This was after over 300 rounds fired with no problems whatsoever.

Since I started investigating the problem, I have had just 1 or 2 not seat properly upon initial load. It's usually somewhere in the middle of the magazine's capacity that it gives the most trouble.

[EndangeredSpecies]

Without quoting all or part of your extended post the VERY next thing you should do is stop grinding, filing, lapping anything. If this gun is new the next move you make should be to call CZ-USA and let them look at it under warranty. There is ZERO reason to be lapping anything on a 75B. These guns do not often exhibit what you describe.
By the way what is your overall shooting background?

Haven't filed or ground anything. Only applied a tiny bit of lapping compound at the feed ramp and rails using a cotton swab after 100 rounds to help smooth things out for the break-in process. Racked the slide about 20 times, then cleaned everything off and lubed it up.
Next 200+ rounds ran like a charm.

I've been shooting for over 40 years, but became more active about 10 years ago when I purchased a couple handguns and started attending a local league. I usually make it out ~ once a month for 50 or 100 rounds, but for a year was there weekly, alternating between the XD45 and the GP100. League took a 2+ year hiatus beginning 2020 and the local ranges were closed, but I got back into it last September. Bought the CZ because of their great reputation for accuracy and reliability. The well-used unit I rented to confirm my choice bore that out. It was great.

I'm no gunsmith, but am a mechanical engineer and fairly mechanically inclined.
I've replaced the sights on all 3 handguns, grips on 2, and the trigger on the XD - which did require just a minimum of fitting to get it to function properly.  The XD runs great, with only 1 FTF in over 800 rounds - when someone else was using it, and I have a feeling she got in the way of the slide on that one.
Never a problem with the revolver.

When I called CZ, 200 rounds in, to express my concern about not hitting to point of aim, they advised me to put at least 500 rounds through it so things can settle in.

[Wobbly]

The reason we like CZ's is that you don't need to do all that stuff that you previously had to do to Colts and Smiths.

Your number one "most likely" cause is poor quality ammo. I scanned your post and didn't see where you mentioned anything about what you're shooting.

[EndangeredSpecies]

Factory recoil spring?  Or lighter.  Lots of people will go to a lighter recoil spring.  I've always run the factory spring and buy factory weight springs for spares (which I haven't yet used).

Magazine springs?  While I've not yet had to replace magazine springs a bullet nose diving into the feed ramp may be an indication of weak springs.  You're are pretty new so it's hard to believe the springs are weak already.  Does this happen with all your magazines?  Some people mark their magazines with numbers/paint so they can keep track of the ones they have issues with.  Another thing I've not had to do, but many people do it.

Waxing the inside and outside of the magazines has always seemed to help mine load easier (so they must feed out easier, too).  Also helps keep them cleaner and protest them from moisture.  That was a good idea and should be a benefit for your magazines.

Have you tried other brands of ammo?  My CZ's doen't seem to "like" Winchester 124 grain FMJ NATO ammo but it functions fine if I don't mind the ugly groups.

All cartridges of the same bullet weight aren't created equal.  The Winchester ammo (124 FMJ NATO) is supposed to be up around 1200 fps muzzle velocity.  What is the advertised velocity for the Federal you've been using?

I've only polished the feedramp on one CZ pistol, my Urban Gray P01.  It would do a nose into the feed ramp failure to feed every now and then and I could feel a spot (like a groove or scratch) that ran across the feed ramp from one side to the other.  Just one out of 11 or 12 CZ's.

Good luck with it.  They are great pistols.  Don't get burnt out on it already.  You know why the CZ is in my belt and not the M&P, SIG, Browning, XD/XDM, Glock,  FNS, etc?  Because the CZs shoot better groups than any of my other semi auto center fire pistols.

Thanks!

All factory springs to date.
I'll try waxing the magazines. I probably should number and track them. The aftermarket magazines seem to run better than the factory ones, but I've had hang-ups with both.

Published MV for American Eagle 124 FMJ's is 1150fps. I have a couple other brands of FMJ, and a box of each of a whole bunch of JHP/defensive stuff, but I haven't tried any of it yet. The Federal AE ran so well from the outset that it's unlikely to be the source of the problem, and I'd rather not add another variable just yet.

I am wondering if, perhaps, CZ used a less-than-ideal magazine spring for the CA-compliant 10-rounders. But how in the world would I check that? Ran fine when new... On advice of others on this forum, I left them loaded with 10 rounds for 3 days prior to my first outing to loosen things up. They do seem slightly easier to load than they were on day 1, but I hope part of that is me becoming more proficient doing so.

[EndangeredSpecies]

The reason we like CZ's is that you don't need to do all that stuff that you previously had to do to Colts and Smiths.

Your number one "most likely" cause is poor quality ammo. I scanned your post and didn't see where you mentioned anything about what you're shooting.

Factory-fresh, new, Federal American Eagle 124gr FMJ's. Published MV 1150fps. Closest thing I could find to "NATO" load for break-in.
If it gave me grief from the outset I'd suspect ammo, but the first 300 rounds (some 50 magazines worth at 6rds/ea for the league I participate in) it ran like a dream.

[tdogg]

So is the round hanging up on the feedramp or is it hanging up prior to fully going into battery and locking up?

Feedramp nosedive issues are mainly tied to magazine issues.  Don't lube your magazines.  Pull them apart clean them with acetone/ipa/brakecleaner then wax them inside and out with your favorite carwax.  Buff clean with dry cloth and reassemble.  When loaded does the top round have upward tension on it?  How about the rounds below it are they stacked nested together or are there gaps?  Stronger magazine springs may help but in general I've found that they aren't needed.  Magazine tuning is a better option but more difficult to describe.

Not fully going into battery could be a couple if things:
Dirty Extractor, have you thoroughly cleaned behind the extractor?  I'd pull it out and inspect it for damage/burrs and make sure it is clean in the channel behind it.  Apply corrosion inhibitor then wipe off.  Lube the spring only (oil) and leave the rest dry.  The round needs to be able to slide up the breechface without any hiccups.

Poor quality ammunition.  I could be short cycling the gun (too weak), too long for the CZ chamber (does it pass the plunk test?), or really dirty (gumming up the extractor, feedramp, chamber, etc...).

Weak recoil spring.  There might be an issue with your recoil spring and it doesn't have enough power to strip and chamber the next round (unlikely if stock).

Cheers,
Toby

[SI VIS PACEM PARRABELLUM]

The mags CZ uses are made by Mec-Gar. There have not been complaints about the 10 rounders being an issue that I've seen here. I'd have another range session with the gun and see how things go. Looks like you're close to 500 rounds or maybe more by now. Unless you are unlocking your wrist at times inducing feed failures I'd contact CZ if the problem persists.

[EndangeredSpecies]

So is the round hanging up on the feedramp or is it hanging up prior to fully going into battery and locking up?

Feedramp nosedive issues are mainly tied to magazine issues.  Don't lube your magazines.  Pull them apart clean them with acetone/ipa/brakecleaner then wax them inside and out with your favorite carwax.  Buff clean with dry cloth and reassemble.  When loaded does the top round have upward tension on it?  How about the rounds below it are they stacked nested together or are there gaps?  Stronger magazine springs may help but in general I've found that they aren't needed.  Magazine tuning is a better option but more difficult to describe.

Not fully going into battery could be a couple if things:
Dirty Extractor, have you thoroughly cleaned behind the extractor?  I'd pull it out and inspect it for damage/burrs and make sure it is clean in the channel behind it.  Apply corrosion inhibitor then wipe off.  Lube the spring only (oil) and leave the rest dry.  The round needs to be able to slide up the breechface without any hiccups.

Poor quality ammunition.  I could be short cycling the gun (too weak), too long for the CZ chamber (does it pass the plunk test?), or really dirty (gumming up the extractor, feedramp, chamber, etc...).

Weak recoil spring.  There might be an issue with your recoil spring and it doesn't have enough power to strip and chamber the next round (unlikely if stock).

Cheers,
Toby

A couple have been caught nose-first on the feedramp. Many more, the slide doesn't close all the way and the round is about 1/4" (+/-) shy of fully seated in the chamber. The ammo is clean, and if I remove the barrel it slides into the chamber freely.
Top round has, what feels like, plenty of tension on it - whether the magazine is loaded with 10, 6, or even a single round. Everything below looks good, and I don't feel any excessive friction or binding on the magazine followers. But I'll clean and wax them to make sure.
I shouldn't even wipe the springs with an oilcloth prior to re-assembly?

I'll try to find some info on removing and cleaning behind the extractor.

League is tonight, but I'm taking the wife out for an early valentines, so I'll 1 more chance to clean things up. Then I'll take SVPP's advice and see how it runs at the range again.

Thanks for the help.

[M1A4ME]

1150 fps for 124's is pretty good.  Sounds like the ammo should be giving your recoil spring a workout.

Mecgar makes mags for CZ.  If they come with a new pistol, or you buy them from CZ they are stamped "CZ".  If you buy them from a magazine dealer they may be stamped "Mecgar" and will be about $10 to $12 cheaper each.  I have had some odd issues with CZ magazines, but not 10 rounders.  They are rare, the problems I mean.

I've not, yet, had the issue you have with the round stopping just short of fully chambered in a CZ.  I've had it in an aftermarket .40 S&W barrel for the M&P pistol and an aftermarket 9MM barrel for another M&P pistol.

If the chamber/barrel isn't uniform, nice and smooth you can have issues.  The round has to align with the chamber and the rougher the surface or sharper the entrance to the chamber you may have issues.  So, how does the brass look on the rounds that "stick".  Stop, eject them, lay them aside and look at the brass.  You may see marks on the brass to show they are getting gouged/scratched and the location/look of the marks can help you figure it out.  That helps you if you can/want to fix it yourself or to help you explain to CZ USA if you call them for a return authorization label to ship it in for repairs.

Couple of mine.

These .40's weren't getting very far into the chamber before hanging up.  You can see the marks on the brass just behind the case mouth/bullet where the brass was being scratched/caught by the rough chamber.  All my polishing didn't fix it and I put the factory barrel back in.  After my recent issue with a different brand of barrel that I did fix I may pull that Storm Lake barrel back out of the box and try again.



On the 9MM barrel the brass went much further into the chamber but still stopped.  I didn't take a picture of the brass but I did take a picture of the barrel.  You can see the shiny brass the barrel scraped off the brass.  That yellow "stain" on the left side entrance to the chamber.  I was getting 1 to 2 failures to chamber out of 5 attempts (hand cycling).  Polished that area with some 600 grit sandpaper on a round rod/punch shaft and I could hand cycle rounds through it from the magazine till I got tired.



Neither may be your issue.  I just shared these so you can compare what I had to what you see with your brass/barrel chamber.

Good luck with it.  A reliable, accurate pistol is what you want.  Usually a CZ75 is just that.

[EndangeredSpecies]

A reliable, accurate pistol is exactly what I want, and the reason I got the CZ75!
Thanks for all the tips, tricks, and ideas.

I found a thread on a TS2 owner having a very similar problem to mine. He had changed to a lighter recoil spring. I have not.
He got more detail on some of the advice I received - which I found very useful.

With barrel removed, every round I've tried easily plunks into and spins within the chamber. My troubles lie elsewhere.
This weekend I'll wax the magazines, inspect to see if any mags require "tuning", and clean behind the extractor. I'm taking a daughter on college tours next week so won't get to return to the range until, probably, the 27th.
If the problem persists, I'll try to capture specifics and perhaps some photos. And probably run it by the shop I bought it from.
I can't imagine 350 rounds would wear out a factory recoil spring, but I do wonder if a new one, or even a slightly stiffer aftermarket one one, might be in order.
Any way to test strength of the spring, or if it's within tolerance range, without sending the gun back to CZ?