CZ75B: Tight chambers?

[kentucky_smith]

So I've been loading up some 9mm ammo with once-fired brass, Berry's plated, Dardas cast, Hornady XTPs, and some Missouri Bullet Co cast bullets.

All lots feed perfectly in my Browning C-series HighPower that I had Novak do some barrel work on and my FM Detective. Thing is, we're having problems with both a CZ75B and a 75b compact not wanting to go completely into battery. COAL is fine and maybe a bit short on all my loads as compared to some factory WWB and Hornady TAP.

I've been fiddling with the crimp using Hornady New Dimension dies in my 550. Wish I had gotten the Dillon or Lee dies instead. Not a big fan of the Hornady seating die.

Anyone had this or a similar experience.

 

[railroader]

On my 75b I have found I need to load some round nose bullets shorter than with my glock. I had some Bear Creek round nose bullets that didn't have much of a taper on the bullet. The bullet would contact the rifling causing the same problem you are talking about, it wouldn't go all the way into battery or if it did the rifling would grab the bullet so I couldn't retract the slide. I started loading them alot shorter and that solved the problem with that bullet. I now now use a truncated cone type bullet which doesn't have this problem. Here's the bullets. The 125rn gave me the problem, the 125 truncated next to it was fine. Mark

 

[blikseme300]

I experienced the same problem. The rounds I reloaded worked just fine in my BHP but when I tried these in my CZ75bd the slide would often not go into battery. I seated the bullets a tad little deeper and all is well. Bullets are cast Lee TL356-124-2R.

 

[burningsquirrels]

i had a problem once with some 9mm bullets i bought. they were an odd weight, and they had to be loaded way short in both the CZ and XD.

i use 1.130" i think on my 9mm loads. bullets are either precision bullets 125 grain, or zero 115 fmj. people also use montana gold 147grn jhp with extreme success.

 

[rbernie]

My CZs and BHPs are just like that; they need bullets that do not have a wide shoulder. My Sigs and M&Ps evidently have a much more generous leade than do the CZ and BHP and can swallow most any bullet shape.

 

[schmeky]

Not an unusual scenario with a CZ. CZ's are "short-throated" compared to many other manufacturers, i.e. the distance from the case mouth to the rifling.

As others have mentioned, seat the bullets for the CZ a little deeper. If you want to find the optimal bullet seating depth for your CZ, use a felt tip pen to color the bullet ogive and find the point at which the ogive just begins to make contact with the rifling, then seat the bullet about .005"-.010" deeper.

These short seated cartridges will still work in your other auto loaders with no problem.

 

[floydster]

In my CZ's I use the barrel as my gauge, seat the bullet until it just clears the rifling, then make a dummy round in that bullet type.
Floydster

 

[burningsquirrels]

^^^ that's what i did for that one bullet that didn't work great... problem was, it ended up being like, 1.010" COL, which was way below the 1.130" the book called for. the problem with that bullet, was that the ogive shape got too wide too soon, if you understand what i'm saying.

 

[Beagle-zebub]

Isn't the CZ-97 the opposite way or something like that? I.e., it often needs cartridges seated long?

 

[rbernie]

the problem with that bullet, was that the ogive shape got too wide too soon, if you understand what i'm saying.

Exactly. The CZ has a very short leade/freebore and the wide shoulder of the bullets jam into the rifling too soon. It clearly was designed around the standard 115gr projectiles. The 'standard' 115gr 9x19 FMJ profile looks like this:

Notice that the shoulder drops away from the body/shank pretty quickly, i.e. the bullet is 'pointy' and starts to get pointy really early on the shoulder. These work well in the CZ, and the CZ's rifling is cut very close to the chamber to give good accuracy with this style of nose.

The HP designs that work well mimic this aspect of the 'traditional' design:

In this example, the shape is a truncated cone shape that is designed to have the bullet seated to the start of the shoulder, i.e. the spot where the bullet angles over into the nose. These also work well in the CZ.

Some cast and jacketed bullets have a less 'pointy' shape, and the start of the ogive is very shallow.

These will not work in the CZ (or any other pistol with a very short leade) unless you seat them deeply. At some point, you can't seat them any deeper without having ogive below the level of the case mouth, and those bullets simply cannot be reliably used in the CZ. Fortunately, there are very few of these style, and they're mostly cast designs.

 

[schmeky]

rbernie,

Excellent tutorial on the original OP's question; your illustrations are top-notch. You guys are the best.

 

[burningsquirrels]

yup, you nailed it.

 

[floydster]

rbernie,
Very informative, excellent post.
Thanks.
Floydster

 

[floydster]

These are the bullet types I use in my CZ 9mm's.
WWB 115 gr.
Hornady 147 gr. HP
124 Cast RN
124 gr.cast TC

 

[kentucky_smith]

The 124 grain Dardas are like this. Playing around with it, the ogive is definitely rubbing against the rifling at 1.13. I seated it down to 1.11 and now they feed fine. Kinda curious about how much pressure thats going to create though.

 

[rbernie]

Exactly so. I switched from the Dardas 124gr to his 125gr and VIOLA! life is grand again.

Here is his 125gr:



And here is the 124gr that's giving us issues:



The 124gr works well in many of my pistols, but it chokes in my HPs and CZs.

 

[billsnogo]

Has anyone had this problem with the Berrys 115grn plated? I just bought some and was unaware of this issues with the cz

 

[belus]

At 115gr I'd be surprised if you have that problem. It mostly shows up with heavier weight (longer) bullets.

 

[NG VI]

I love THR

 

[Craig M. Arnold]

[QUOTEHas anyone had this problem with the Berrys 115grn plated? I just bought some and was unaware of this issues with the cz
][/QUOTE]

I've loaded a lot of these bullets and they work fine in my CZ pistols.

Best regards.

 

[tekarra]

Excellent post with many thoughtful articles. Sticking to factory loads, as opposed to re-loads, I have several cZ 75Bs and find that some will require the slide to be pushed closed while others will go into battery unassisted. Granted this happens seldom, but it is indicative of chamber size. It is not a dirty chamber issue as I clean my pistols thoroughly after every shooting. Granted, it does not happen often as I have observed it only with Brown Bear ammunition, When it has occured, I just switched to another pistol. The joys of owning several cZs!

 

[billsnogo]

I love THR

Ditto

Thanks for the assurance. I assume than that it starts to rear it's head with 124+gr bullets?

 

[belus]

I shoot 130gr lead at 1.143", but its a truncated cone style bullet. Its more about geometry than weight, but heavier bullets take up more case volume (they're longer) and generally have to be seated further out to avoid compressing bulky powders.

I've had no trouble with factory loaded 124gr Gold Dots, or 124gr Golden Sabers if you're concerned about defensive ammunition. They're the only two I've tried.