New CZ 75 B Jamming

[tdogg]

Glad you got found the cause and that your latest range trip was a success!  There is a ton of really good ammunition information shared that is applicable across platforms on this forum.  If you ever want to get into reloading this is the place to start.  There are members here that will jump start the learning curve and have you up and producing safe, quality ammo in no time.

As far as never buying Fiocchi again, I wouldn't go that far.  Now that you understand the issue, you can make informed purchasing decisions with your barrel in hand!  Fiocchi isn't the only ammunition that could pose a problem, there have been numerous brands over the years that fail plunk testing.

Good luck and happy shooting!

Cheers,
Toby

[BradJL]

Toby -

Yes, those are very good points. Honestly, now that I’m on the other side of it, I’ve gone from feeling frustrated to accomplished. There’s so much to learn and that’s part of what makes this an engaging hobby.

[Phyffe]

I think the pandemic and the ammo shortage that followed resulted in a lot of substandard stuff coming onto the market.

When I first got my P10S, I bought 4 boxes of Armscor FMJs to break the gun in (I live in the Philippines and this brand is by far the cheapest available since its made here). The jamming was just as you described it and was alarming.

I immediately bought a slightly more pricey box of PMC JHPs and a MUCH more pricy Federal HSTs and I fired off mag after mag with zero problems.

I also own a 75B and I noticed that some of the rounds that failed the plunk test on my P10S would actually pass on my 75B barrel, but I've since sworn off Armscor ammo.

[bonj]

We know that CZ barrels are notoriously short throated and certain ammo will be an issue.

Why does CZ short throat its 9 Luger barrels?

Probably been discussed many times in other threads but I think it has to do with the truncated cone 9mm bullets that were used in Europe years ago. Those bullets had little to no shoulder protruding from the case mouth so bullet contact with the rifling was never an issue.
You would think they would just lengthen the freebore at this point which would be a simple operation given the issues like this that prevail.

I have used many truncated cone 147 gr. 9mm bullets in my CZ 75B omega and never had an issue, of course after having my barrel throat lengthened by CZ.

[Tim_B]

When you get one stuck in the chamber like that then use this trick that a range master taught me when I had one get stuck:
With the gun pointed downrange grip the slide as tightly as possible with one hand, I mean tightly to the point your hand is shaking, then use the web of your other hand to strike hard on the area of the back of the grip where the web of your hand normally fits when shooting.  Strike it hard and fast like this.  It imparts much more force to pull back the slide and eject the round than you can impart by pulling back the slide the way you normally do.
I had some winchester white box round get stuck the same way the original poster's fiocchi got stuck.  After freeing the stuck rounds I looked at them side by side with others from the same box and  I could see that the case was cut slightly too long and the mouth was not taper crimped like the ones of proper length. 

[Minfred]

Good thread, I keep learning from this forum.

[M1A4ME]

I started carrying an old GI 6" steel cleaning rod in my range bag.  Only had one stick since I started carrying that old cleaning rod to the range and it knocked it loose easily.

They aren't really jammed in as bad as they feel like they are.  It's a combination of physics that makes it so tough to pull the slide back.  That and our weak modern man hands/fingers.

[Davehb]

3 brands of firearms I know of are having issues with the Fiocchi.
For any brand of Modern compacts I would do the plunk test.
I’m thinking gun manufacturers are following CZ.
The short freebore I believe is part of what makes a CZ so accurate.
Back in my reloading days I had a Ruger P89 that wasn’t very accurate and lots of freebore. After tailoring loads for it to reduce jump the bullet had to make before hitting riflings I could get them in a pie plate at 100yds.

Some guns some buddies have bought such as m&P shield ez, and a Glock compact had the same problems with the Fiocchi though the Glock could use the 115 grain but no heavier grains in fiocchi.
The EZ had issues with both.


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[Wobbly]

The first time I took it to the range, it was badly jamming, both sometimes after racking it and sometimes in the middle of firing a magazine. What was so odd was how strong the jams were. There would only be one bullet inside (so during times when it was in the middle of a magazine, the spent cartridge was successfully ejected) and the slide would be about 90% closed. It was so hard to unjam it that I didn't have the strength to pull back the slide to unjam it. Each time I had to call the range officer, who also didn't have the strength....

This could also be a chambering issue, cause by poorly sized cartridge cases.

• Unlike 98.7% of the other ammo, the German 9x19 Luger case uses a TAPERED CASE. Those who stop and consider for 30 seconds, will find that means the chamber is also cut with a taper.
• Cartridge cases fit into their chambers with clearances smaller than the diameter of a human hair. So there is very, very little room for error.




When brass is not sized correctly (as shown above), gets misshapen during processing, or ends up with any "metal flash" on the case mouth, then the cartridge will enter the larger breech end of the chamber, but due to the decreasing dimensions of the taper, "jam" half-way in as the OP described. The taper of the chamber allows a wedging effect to take place... which is why it's so hard to unlock the slide when the fault occurs.

However, it's not all of the OP's cartridges. This is why the fault shows up at random times and can't be explained by throat/ freebore dimensions, extractor issues or faulty mag springs.

For those who wish to research, this is all covered in the Stickies of the Ammo Sub-forum. https://czfirearms.us/index.php?topic=78873.0

[Wobbly]

Why does CZ short throat its 9 Luger barrels?

Why do people persist in not reading the explanation already provided in the Stickies ?

https://czfirearms.us/index.php?topic=114239

[M1A4ME]

Why does CZ short throat its 9 Luger barrels?

Why do people persist in not reading the explanation already provided in the Stickies ?

https://czfirearms.us/index.php?topic=114239

Because we're MEN.  And MEN don't need to read instructions. 

Probably several reasons.  New and don't know where to look.  New and in a hurry.  Long time member and in a hurry.  Figure it's easier to have someone answer than to look it up for ourselves.  More I haven't thought of.

You make some hellaciously good diagrams/drawings and I've found myself copying them to my laptop a lot since I've been a member here.  A lot more people would understand more about their guns and their issues if they looked at those things and then asked questions about stuff that still wasn't clear to them.

[Davehb]

The first time I took it to the range, it was badly jamming, both sometimes after racking it and sometimes in the middle of firing a magazine. What was so odd was how strong the jams were. There would only be one bullet inside (so during times when it was in the middle of a magazine, the spent cartridge was successfully ejected) and the slide would be about 90% closed. It was so hard to unjam it that I didn't have the strength to pull back the slide to unjam it. Each time I had to call the range officer, who also didn't have the strength....

This could also be a chambering issue, cause by poorly sized cartridge cases.

• Unlike 98.7% of the other ammo, the German 9x19 Luger case uses a TAPERED CASE. Those who stop and consider for 30 seconds, will find that means the chamber is also cut with a taper.
• Cartridge cases fit into their chambers with clearances smaller than the diameter of a human hair. So there is very, very little room for error.




When brass is not sized correctly (as shown above), gets misshapen during processing, or ends up with any "metal flash" on the case mouth, then the cartridge will enter the larger breech end of the chamber, but due to the decreasing dimensions of the taper, "jam" half-way in as the OP described. The taper of the chamber allows a wedging effect to take place... which is why it's so hard to unlock the slide when the fault occurs.

However, it's not all of the OP's cartridges. This is why the fault shows up at random times and can't be explained by throat/ freebore dimensions, extractor issues or faulty mag springs.

For those who wish to research, this is all covered in the Stickies of the Ammo Sub-forum. https://czfirearms.us/index.php?topic=78873.0

Excellent article.
You make it tempting to get reloading equipment again.


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[armoredman]

Do it - I haven't bought range ammo in decades, make my own. 124gr Lee cast lead powdercoated loaded to 1.095 and every CZ loves it. Of course, finding primers right now is truly fun...not.
BradJL, welcome to the Forum, glad you are here! I would also see if CZ can relieve the throat a little bit, can't hurt. 

[Wobbly]

Excellent article.
You make it tempting to get reloading equipment again.

Thank you for the compliment. We try to make the Ammo & Handloading sub-forum a place for member education. There's a LOT more info there.

Actually, there are 3 separate issues with the 9x19 Luger that could cause that same apparent "jamming". Two of these are due to the tapered chamber, which (for all intensive purposes) is really found nowhere else but in the Luger cartridge...
• Poorly sized taper crimp
• Expanded heads from spent "9 Major" cartridges
• OAL too long for the chamber

Only lots of testing, measurements and special die setups prevent each of the 3.

Hope this helps.