CZ SP-01 & 147gr 9mm bullet Chambering Problem.

[thai562]

Hi Calgunners,

I went to the range today with my new CZ SP-01 and discovered something odd.
I reload 2 types of 9mm, 124gr and 147gr, both are from Zero bullets. I have use these bullets on 3 other 9mm Sig pistols for years now, with no problem.
At the range today, I discovered that the CZ would not completly chamber a 147gr bullet. Ended my range trip early, went home to checked everything out.
After taken multiple measurement of the two rounds, I discover the cause.
Zero made the 124gr bullet more like a cone shape. Starting from the top of the case, the 124gr starts to reducing its diameter as you move closer to the tip.
The 147gr on the other hand, continues it's 9mm diameter for about 1/8" above the case before it starts to reduce its diameter and turning into a cone.
For this reason, the rifling make contact with the bullet before the round is completely seated.
I marked the 147gr round with a Sharpie, and placed it in the barrel and rotated it, to see where the contact area is.


This is how the 124gr bullet completly chamber look like.

This is the 147gr, not completly chamber. A little over 1/16" stick out passed where it suppose to.


My question is this. Because these two rounds work fine on my other 9mm, I like to know which is out of spec. The CZ barrel? or The Zero's bullets?
Have you guys shoot 147gr ammo out of CZ 75 9mm pistol before?

[Cedone12]

Tagged. Sorry your range day was cut short! This is a great question! I don't reload but I will in the near future.

[The Shootist]

That's crazy hmmmm.....I'd like to hear someone's thought on this interesting.

[Mr. Patis]

I shot 147 gr from freedom munitions with no problems in any of my CZ75

[BEE]

You may need to seat the 147gr bullet a tad deeper. Refer to the "How to determine Max OAL for a CZ Pistol" sticky in the handloading section on czfirearms.us forum. That thread will guide you to get the best COL for your particular barrel and whichever projectile you are reloading. Try loading up some dummy rounds and various lengths to see which would chamber the best.

Thread Link - How to determine Max OAL for a CZ Pistol

[midvalleyshooter]

BEE is correct. The SP01 is a great pistol but they have short chambers and you have set up the OAL shorter than for some other pistols.

[EMR]

Tagged! I can get my 124gr RNs to fit in my CZs, but I wasn't able to get my flat points to fit.

[BoJackUSMC]

Interesting... tagged as well..

[BEE]

Tagged! I can get my 124gr RNs to fit in my CZs, but I wasn't able to get my flat points to fit.

It's do-able; just have to load them rather short and lower the charge. To give you an idea, for my 75B SA I was loading Berry's hollow base flat points at 1.035" 4.1grns of HP-38. Didn't help that my barrel had even a shorter chamber than other CZ's..

[Joseblanco]

Here is how I deal with this

All of my case's are square at the mouth , matching head stamps and are loaded by case length. With the barrel out of the slide drop an empty case in the chamber and measure the total length from the base of the case to the end of the barrel. Load a bullet with no crimp and drop it in the barrel. Keep decreasing the OAL until you come up with the same length as the empty case. Then decrease the overall length by about .003, I use a comparator to measure the overall length one third down the ogive. Each bullet I shoot is loaded this way . You can play with the set back if your looking for the best jump. In my CZ75 b sa I use the .003 jump and it works well for me..

Joe

[jdogg2000]

CZs are well known to have short chambers, just like the PPQ. It's not unusual to have a COAL of 1.085" or less.

[thai562]

Conclusion: This is a CZ's things, and really not a Zero's bullets problem.

After reading some of your's posts, and some from the CZ's forum. It look like this is a common thing for CZ's to have short chamber, making some heavier bullets of the range not to chambered.

Bases on my measurement, I will have to seat all my 147gr bullets .050" lower for them to chambered my CZ's. .050" is a significant amount, I will have to lower some of them in increment and check for over pressure before doing it to all of them. Good thing I always charged my pistol rounds on the low end, so I have some room. After this current batch of 147gr, I will avoid 147gr 9mm in general.

As for people who buy their ammo, this problem seem to happen to some factory 147gr also. So test a few out before buying 1000 round of them.

[NiteQwill]

I've had to load my 147 gr Xtreme bullets to 1.145 OAL for CZ's. No issues with chambering on any of my CZ's (8 total - I shoot the same load across all platforms).

However, due to cost, I have forever switched to 124 gr bullets.

[Tok36]

How to determine Max OAL for a CZ Pistol

http://www.czfirearms.us/index.php?topic=34225.0

[Carcassonne]

Hi Calgunners,

I went to the range today with my new CZ SP-01 and discovered something odd.
...
At the range today, I discovered that the CZ would not completly chamber a 147gr bullet. Ended my range trip early, went home to checked everything out.

My question is this. Because these two rounds work fine on my other 9mm, I like to know which is out of spec. The CZ barrel? or The Zero's bullets?
Have you guys shoot 147gr ammo out of CZ 75 9mm pistol before?

It is normal for CZ guns.

CZ has a tighter chamber and shorter throat (if that is the correct term). That is why CZ guns are more accurate out of the box.

I reload lead bullets, and there are quite a few bullet profiles that won't work in my SP-01.



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