Barrel Size

[wv109323]

 I was wondering what the bore size and tolerance of a CZ 75B Omega in 9MM is?

[SI VIS PACEM PARRABELLUM]

Uh well it's a 9mm. Barrels like fingerprints are all different so as is the norm in handloading you slug YOUR particular barrel and size bullets accordingly.

[wv109323]

I have slugged the barrel and it comes to .3562 with a hard slug. I drove a pure lead slug through and got .3565. That seems to me to be a little large. I was wanting to know what CZ's size and tolerance is?
When I go with a bullet big enough for the bore, I run into chambering problems with a cast bullet. So far I can not get a .3572 powder coated bullet to shoot accurately at speeds that approach a PF of 125 to 130.
 In general I can not get any cast or powder coated bullet near the 130 PF to be accurate. I have tried 120, 125 ,135 and 147 g. Bullets. The 120 and 125 have been tried at .3565 , .3572, .3577 and .3582. The 135 and 147 are .357 and .356 respectively.
 I have so far used only W231 powder. I am going to try Bullseye and Unique.
I have some 115 jacketed and 124 JHP loaded to test as a reference.

[SI VIS PACEM PARRABELLUM]

If you want an actual spec the most likely place you'll find it is CZ-USA give them a call. How does the gun shoot with factory ammo? You need to shoot the gun with quality factory ammo to have an idea of it's accuracy potential. Working up an accurate load is obviously a process and from what I can see so far you've not even scratched the surface given you've only tried one powder. There are a multitude of good powders that work well in 9mm and just as many bullet options.
Some of the most accurate cast 9mm's I ever loaded were with a 133 gr. cast SWC on top of 6.2 grains of Herco. If I use cast bullets in anything I cast my own so there's that too.

[Earl Keese]

wv109323, it would help if you tell us your definition of accurate. What type of shooting are you doing? The bores of most of my CZ's are on the large side as well so I load with .357 coated lead bullets. For practical pistol matches and steel challenge I've found accuracy to be acceptable. I didn't care for my results with win231, but have been pleased with Sport Pistol and a few different brands of coated lead 135rn.

[Wobbly]

• Lots of bore slugging has been done here before. Have you tried using the Search routine ? Simply enter the multiple words you want in your search, separated by a space. I tried "slug bore" and lots of threads came up with both words in a single sentence.

I agree, CZ's tend to run a tad large but I don't want to quote a number off the top of my head and get it wrong. I have been known to transpose digits.

• I don't shoot a lot of lead for health reasons, but when I have, then coated 0.357" bullets was enough to do the job. I agree, when you go much bigger then the size starts to raise chambering issues.

• I know powders are hard to find right now, but you'll want to try some more. W231/ HP-38 is a fantastic start-up powder for the novice, with many attributes that make it docile and very forgiving, but super accuracy is not one of the traits. Look at several "powder burn rate charts" and see what you can find that's at that "speed" and slightly slower. Sport Pistol, N320, N330, Bullseye, Silhouette, maybe even WSF, BE-86 or Ba9. I really don't think you'll be happy with Unique, or super slow powders like CFE Pistol and HS-6.

http://www.accuratepowder.com/wp-content/uploads/2010/12/burn_rates.pdf
https://www.brownells.com/userdocs/learn/Hi-Res_Vihtavuori_Burn_Chart.pdf

Hope this helps.

[wv109323]

Earl- I would like to get involved in USPSA and shoot a CZ 75. My definition of accuracy would be 2" CTC 10 shots at 20 YARDS from a Ransom Rest with a PF of 125 to 130. I don't think I will ever see 1 1/2", 2-21/2" should be doable. So far I have not be able to do that. I have stuck with W231 because I have about 10 pounds of it. I hate to buy a pound of powder just to eliminate it for accuracy. I may have to buy a box of factory ammo but who knows what is accurate in a CZ. I just went through testing a friend's STI 9MM and the cheap Federal ammo( I think it was called Champion, red and blue box) outshot the expensive match ammo. My results so far with .357" Diameter bullets of 124, 135 and 125g. have been 4 1/2" to 6 3/8" when I approach the required 125 power factor.
Wobbly- I did a search for "bore size" in reloading and got three responses. Two were mine and one was yours. I looked under several other topics and did not find the answer I was looking for. What is CZ dimension and tolerance for a 9MM bore? I will call CZ to find the answer. I am going to try Bullseye powder.
 My opinion of the CZ pistol is that it was never manufactured to shoot cast bullets. Knowing what I know now I would have bought another brand.

[SI VIS PACEM PARRABELLUM]

My opinion of the CZ pistol is that it was never manufactured to shoot cast bullets. Knowing what I know now I would have bought another brand.

Your problem is you know very little at all and seem to be completely unwilling to do the hard work to find a load that will allow YOUR particular gun to perform they way you want. Your refusal to buy different powders is clear evidence of that. Those of us who have handloaded for decades understand the value of different components and the need to spend time and effort with them to get where we want to go. I've had 30 different powders on the shelf at times in the past that's just what has to be done.
I've shot literally tens of thousands of cast bullets through my CZ's with stellar results excellent accuracy and 100% reliability. If you won't do the work you just simply won't get the result.

[M1A4ME]

The Federal Champion 115 grain FMJ shoots very well in all my 9MM CZs.  P09, CZ75 Compact, P01, etc.

Winchester white box 115 FMJ do not shoot as well and are dirtier/longer clean up time.

The Winchester 124 grain FMJ NATO rounds don't do as well in my CZs as the Federal ammo either.  The M&P 2.0 5" loves that stuff (well, with the Apex barrel in it anyway).

[SI VIS PACEM PARRABELLUM]

The only other thing that could be a consideration is being a regular metal framed CZ it could benefit in the accuracy dept. with the addition of the CGW barrel bushing on the chance that the factory part is in the higher end of the tolerance range.

[Earl Keese]

Earl- I would like to get involved in USPSA and shoot a CZ 75. My definition of accuracy would be 2" CTC 10 shots at 20 YARDS from a Ransom Rest with a PF of 125 to 130. I don't think I will ever see 1 1/2", 2-21/2" should be doable. So far I have not be able to do that. I have stuck with W231 because I have about 10 pounds of it. I hate to buy a pound of powder just to eliminate it for accuracy. I may have to buy a box of factory ammo but who knows what is accurate in a CZ. I just went through testing a friend's STI 9MM and the cheap Federal ammo( I think it was called Champion, red and blue box) outshot the expensive match ammo. My results so far with .357" Diameter bullets of 124, 135 and 125g. have been 4 1/2" to 6 3/8" when I approach the required 125 power factor.
Wobbly- I did a search for "bore size" in reloading and got three responses. Two were mine and one was yours. I looked under several other topics and did not find the answer I was looking for. What is CZ dimension and tolerance for a 9MM bore? I will call CZ to find the answer. I am going to try Bullseye powder.
 My opinion of the CZ pistol is that it was never manufactured to shoot cast bullets. Knowing what I know now I would have bought another brand.

Instead of chasing a specific power factor, I would suggest ladder testing to find the most accurate load with your chosen components. My ammo ended up at 135pf, I don't recall the actual velocity without my notes handy. If you plan on competing in USPSA, you'll likely want to stick with faster powders like Sport Pistol, N320, etc. Going after the lowest PF isn't worth the hassle, and depending on conditions you may not pass chrono at a match. CZ's are plenty accurate enough for USPSA, IDPA, Steel Challenge and so on. Lots of us use coated lead without issue. Stick with it and I bet you find the load your looking for.

[tdogg]

+1 to what Earl said.

I've shot 180pf loads because that was where I found accuracy (major).

You can also play with seating depth assuming your not at max load.   

Cheers,
Toby

Sent from my SM-G950U using Tapatalk

[Wobbly]

I would like to get involved in USPSA and shoot a CZ 75. My definition of accuracy would be 2" CTC 10 shots at 20 YARDS from a Ransom Rest with a PF of 125 to 130. I don't think I will ever see 1 1/2", 2-21/2" should be doable. So far I have not be able to do that. I have stuck with W231 because I have about 10 pounds of it. I hate to buy a pound of powder just to eliminate it for accuracy. I may have to buy a box of factory ammo but who knows what is accurate in a CZ. I just went through testing a friend's STI 9MM and the cheap Federal ammo (I think it was called Champion, red and blue box) outshot the expensive match ammo. My results so far with .357" Diameter bullets of 124, 135 and 125g have been 4 1/2" to 6 3/8" when I approach the required 125 power factor.

1. No one is keeping you from shooting USPCA. Lots of people shoot that with CZ75's.

2. If you are stuck on W231, then an option to regain accuracy is to shoot jacketed bullets. May I suggest you order some Precision Delta 124gr FMJ or JHP, or Rocky Mntn Reloading 124gr Match Winner bullets and start there.

My opinion of the CZ pistol is that it was never manufactured to shoot cast bullets. Knowing what I know now I would have bought another brand.

Oh, please! Give us a break. There are NO pistols on the market "manufactured to shoot cast bullets". The simple truth is, people go out, do the testing, and discover what works.


All the best.

[wv109323]

 I know no one is keeping me from shooting USPSA but I have problems with the pistol/ammo that makes it unreliable. With my barrel that I consider to be oversize, I had to shoot a .3582 bullet. That is with my cast bullet. Bullet diameter smaller than that and I get tumbling. Even at .3582 I question that all the bullet holes are round. With a bullet large enough to keep it from tumbling the ,3582 bullet hits the grooves of the barrel(.3562) and shaves a little lead. After a few rounds and you get a round that will not go into full battery. You can not shoot USPSA will a firearm that will not fire after several rounds. his is a separate story that precedes my recent quest.
 I choose the 125-130 power factor because that is what is legal for the competition and my cast bullet alloy is not No. 2, it is range scrap and COWW. I thought the lower I could keep the velocity the less likely to have leading.
 As far as trying different powders, I live in the middle of nowhere, I mean nowhere. I doubt I could drive in any direction for 2 hours and find a gun store with a pound of powder of any kind. Let alone a specific powder. I could mail order but 1 pound of powder plus haz. mat. is not a bargain. You would have $50 in a pound of powder that may not be the answer.
 As far as not paying my diligence to find a load I can offer up the following.
 I want to shoot my cast bullet load for economic reasons. I am retired on a fixed budget and do not have the cash to buy jacketed bullets for practice and matches. I do have the time to cast bullets.
 About the CZ pistol, I find several comments that say they have large bores. My pistol had .006" of leade before the bullet hit the rifling. The .3582 cast bullet had to be seated extremely deep to keep it off the rifling and have reliable functioning. A bullet hitting the rifling would not allow the slide to go into battery, Seating the bullet that deep into the case would size the bullet down and sometimes swell the case to a point the round would not chamber. That is my reasoning that the CZ pistol was not manufactured to shoot cast bullets. Large bores require large cast bullets. Large cast bullets that need to be seated extremely deep cause coke bottle shaped rounds. Coke bottle rounds do not fit in a chamber. I had my share of malfunctions in matches so I decided to skip competition until I got a pistol that would function through a match.

[SoCal]

Thousands of people shoot USPSA with CZ's and cast bullets.  I shoot different CZ's in USPSA, there is nothing about a CZ that precludes it from shooting quality cast bullets accurately.  Either there is a defect in your pistol or in your loads.  If in the pistol contact CZ for warrant repair.