Casting for CZ75... UGH:(

[kingemandigger]

Just received my new CZ75 B Stainless. Woo hoo! What a beautiful gun.

So, I want to shoot cast out of this baby just like with my other pistols. Now to develop a load. This is interesting... There is a pronounced lip that sits right up against the case mouth. Well, I guess I have some experimenting to do.

Fast-forward to now. I have just tested the first batch of boolits in my CZ and am both impressed at their accuracy and lack of leading, and perplexed at a condition that has developed due to that very lip.

I have two different molds for the 9mm; The lee TL356-125-2R and the lee 358-125-RF. I chose the .358 mold because CZs are notorious for having large bores. These cast to .358-.359 diameter. I loaded one over 4.5 grains of WSF to the crimp grove, tried to chamber it, and it got caught on that lip. I ended up having to seat the boolit to .980 for the round to properly seat, and drop my charge to 4.2 grains, a minimum charge. These, when fired at the range, performed great. They were extremely accurate, and produced no leading. Their only vice was that that pesky lip would size the boolit when firing, and small lead shavings would build up under it. After every 25 rounds or so my loads would not chamber properly and leave the slide only partially closed. Only after shaking out a small ring of lead would they function properly again. Also, upon cleaning, (after 150 rounds) there were specks of lead throughout the action that could be peeled off with a small screw driver.

How annoying, the rounds functioned perfectly and I would be happy to use them as my go-to range load if it wasn't for this dastardly condition. So, for my fix... The only other mold I have is the .356 TL. This casts to .3565-.357 and doesn't have quality lubricating properties IMO. However, I figured that if that ring was already sizing my other rounds, this may solve my problem, being slightly smaller.
Thus, I popped one over 4. 7 grains of WSF, leaving one ring exposed and tried to chamber it. This is what I found.

The one on the left was difficult to extract, and was slightly sized around the exposed ring, but not quite as badly as the .358. I thus dropped the charge to 4.5 grains and seated that top ring just below the case mouth, producing an oal of 1.078. I will report after trying 100 of these. My biggest fears are that they lead, or that they still produce lead shavings. Perhaps I will have to revert to the J-word. nooooooo

My question is, does anyone have any experience with loading for CZs or any advice. Thanks in advance.

[Larry Gibson]

With either bullet use the barrel (disassembled from the gun) as a "chamber gauge". The loaded round should "thunk" into the chamber when dropped it. The case head should be even with or below the barrel hood (extension). Let your own barrel/chamber determine what the correct oal is, not some arbitrary oal the books or we might give. Seat either bullet just deep enough and taper crimp enough that the loaded round thunks in with no resistance.

Also I have been dealing with CZ 9mms, particularly CZ75s, for many years. I've had my own since '91. I've not found them to be "notorious for having large bores" at all. I size the bullets .357 for the .356 groove diameter of my own CZ75. I also load a lot of 9mm for use in other 9mms including subguns and have never had leading with .357 sized cast bullets. It would appear your own CZ75 does not have a "large bore" either because of the lead scraping you are getting at the throat. I suggest the 4.2 gr load of WST with either bullet. I suggest you size the bullets at .357.

Larry Gibson

[kingemandigger]

Thanks for your input. The lee TL boolits I have are .357 diameter, so hopefully they will work well. I just hope they don't cause the same lead scraping effect.

[Ed_Shot]

The Lee 356-125-2R (standard lube) works great in my 75B. I now size all 9MM to .358. I used to size .357 but got tired of changing sizing dies and found that .358 worked perfectly also in CZ'z, Browning's and Glocks w/ LW barrels.

As Mr. Gibson suggests, I found the MAX COAL for 356-125-2R in my 75B barrel to be @ 1.065. To allow for press variation I load 356-125-2R to an OAL of 1.055. My favorite load for 356-125-2R is Blue Dot 5.8 gr @ 1075 fps. My most accurate load for the CZ is a Lyman 358242 (120 gr) sized .358 over Blue Dot 6.0 @ 1100 fps.

I'm surprised you have to use an OAL of .980 with 356-125-2R but I have never tried to use a TL boolit.

[kingemandigger]

Sorry about the confusion. I loaded the lee 358-125-rf to .980, not the .356 tl. Thanks for the info

[blikseme300]

Please provide sources for the notorious bore size in CZ's. The scraping you are referring to is caused by the short leade common to the tight tolerances that this manufacturer is known for. The plunk test should show that your boolits are not seated deep enough. Published OAL is merely a guideline and for specific combinations only.

The usual warnings apply about load data, use at own risk.

My boolits of choice for the 9mmP are the Lee 120TC sized at .357 and seated that the shoulder barely shows. Taper crimped to remove belling over 4.2gn of HP38. My favorite range 9mm pistol is a CZ75BD and it is very accurate with the combo I listed. Cleaning is simple with no leading ever.

[GMT210]

I believe the pronounced lip that you are referring to is what the cartridge is designed to head spaces off of, the end of the brass case is supposed to stop at the lip. If you try to load significantly oversized or long OAL cartridges they will either wedge themselves into the throat rifling or they will not allow the case to seat against the lip, which may lead to the firearm not returning to full battery (action does not close all the way), it can also lead to a severe overpressure situation.

Slug your bore, and know your bore size, don't guess. I also have a CZ 75D-PCR 9mm that has bore of 0.3555 & I size to 0.3575

I will load a bullet long into a pre-fired case, there is just enough neck tension to hold the bullet, but still allow it to push back. I will then drop this load into the barrel and with my thumb seat the cartridge against the head space lip. Remove the cartridge and measure the overall length, this is the MAX OAL for this case & bullet combination. I will usually reduce this measurement by 0.005-0.010 and use this as my MAX Safe OAL.

GMT

[MtGun44]

"this is my MAX OAL". . . . . . Assuming it fits the magazine.

Bill

[ipijohn]

I have loaded many 10's of thousands of LEE TL356-125-2R'S and shot them in any of my 15 or so CZ's sized to .357. I have one load 4.4 grn of HP 38 seated to 1.070 OAL. Been doing it for years the same way and don't plan on changing unless I decide to start powder coating them. If I start powder coating them I will still load to 1.070 OAL but might have to reduce the powder depending on how they Chrono.

[ipijohn]

Just received my new CZ75 B Stainless. Woo hoo! What a beautiful gun.

So, I want to shoot cast out of this baby just like with my other pistols. Now to develop a load. This is interesting... There is a pronounced lip that sits right up against the case mouth. Well, I guess I have some experimenting to do.

Fast-forward to now. I have just tested the first batch of boolits in my CZ and am both impressed at their accuracy and lack of leading, and perplexed at a condition that has developed due to that very lip.

I have two different molds for the 9mm; The lee TL356-125-2R and the lee 358-125-RF. I chose the .358 mold because CZs are notorious for having large bores. These cast to .358-.359 diameter. I loaded one over 4.5 grains of WSF to the crimp grove, tried to chamber it, and it got caught on that lip. I ended up having to seat the boolit to .980 for the round to properly seat, and drop my charge to 4.2 grains, a minimum charge. These, when fired at the range, performed great. They were extremely accurate, and produced no leading. Their only vice was that that pesky lip would size the boolit when firing, and small lead shavings would build up under it. After every 25 rounds or so my loads would not chamber properly and leave the slide only partially closed. Only after shaking out a small ring of lead would they function properly again. Also, upon cleaning, (after 150 rounds) there were specks of lead throughout the action that could be peeled off with a small screw driver.

How annoying, the rounds functioned perfectly and I would be happy to use them as my go-to range load if it wasn't for this dastardly condition. So, for my fix... The only other mold I have is the .356 TL. This casts to .3565-.357 and doesn't have quality lubricating properties IMO. However, I figured that if that ring was already sizing my other rounds, this may solve my problem, being slightly smaller.
Thus, I popped one over 4. 7 grains of WSF, leaving one ring exposed and tried to chamber it. This is what I found.

The one on the left was difficult to extract, and was slightly sized around the exposed ring, but not quite as badly as the .358. I thus dropped the charge to 4.5 grains and seated that top ring just below the case mouth, producing an oal of 1.078. I will report after trying 100 of these. My biggest fears are that they lead, or that they still produce lead shavings. Perhaps I will have to revert to the J-word. nooooooo

My question is, does anyone have any experience with loading for CZs or any advice. Thanks in advance.

Info from the CZ forum. http://www.czfirearms.us/index.php?topic=60696.0 One can try to explain this but the cartoon in the first post explains it all.

[Brenden]

I believe the pronounced lip that you are referring to is what the cartridge is designed to head spaces off of, the end of the brass case is supposed to stop at the lip. If you try to load significantly oversized or long OAL cartridges they will either wedge themselves into the throat rifling or they will not allow the case to seat against the lip, which may lead to the firearm not returning to full battery (action does not close all the way), it can also lead to a severe overpressure situation.

Slug your bore, and know your bore size, don't guess. I also have a CZ 75D-PCR 9mm that has bore of 0.3555 & I size to 0.3575

I will load a bullet long into a pre-fired case, there is just enough neck tension to hold the bullet, but still allow it to push back. I will then drop this load into the barrel and with my thumb seat the cartridge against the head space lip. Remove the cartridge and measure the overall length, this is the MAX OAL for this case & bullet combination. I will usually reduce this measurement by 0.005-0.010 and use this as my MAX Safe OAL.

GMT

I find this to be the case, especially the first paragraph. CZ75 have a very tight chamber area, many people have it reamed to avoid the troubles expressed by OP.

[dubber123]

I'm not sure if it was mentioned, but the round on the left that gave hard extraction shows a bit more case mouth flare remaining than the shorter one to the right. Variances in case length can make this difficult to control. I like seating and crimping in 2 seperate steps using a taper crimp die. It doesn't require much of a bell to be left to stick a round in a chamber. Good luck.

[390ish]

I cannot get TL boolits to work in 9mm. I gave up and shoot the lee 120 TC. Think it is a 120. Just Alox and size .358 and charge with 4.2 hrs HP-38. Shoots well out of my CZ-75. Non of my sigs will shoot cast. Best cast 9 shooter I have is a ruger p-95.

[blikseme300]

The tight chamber plays a large part in the intrinsic accuracy of these pistols so reaming it is only advantageous for using ammunition of loose specifications. Good reloading practice eliminates the need for reaming IMO.

[ipijohn]

I have a bunch of CZ's in many calibers. They all shoot Lee TL boolits accurately if the boolits are loaded correctly.

[HeavyMetal]

The Lee tumble lube 9mm RNL has a "Lip" formed by the top lube groove on the TL design. Loaded to "suggested" OAL's allows this section of the boolit to extend past the case mouth, and come in contact with, the chamber area "lip" where the boolits start contact with the rifling.

Hope I said that clearly, LOL!

Most likely getting same results with 125 RF 358 diameter. Reducing diameter of the 125RF will result in much better chambering.

I think the OP has read a bunch of posts on leading in the 9mm and is a tad gun shy of the leading issue.

I will suggest the OP buy a 125 2R standard lube groove mold from Lee and try it or get some 125 RF sized to 356 and try them.

Another suggestion for the barrel "plunk" test before firing to determine an OAL for the specific gun. Reducing OAL increase's pressure in any cartridge and the little 9mm can get real high real fast with minimal reduction's in OAL.

[Floydster]

I run all my cast bullets in my CZ's at .356

[MtGun44]

Most 9mms do best at .357 or .358, but some have very tight chambers and
with certain thick walled brass, will not chamber larger diams. I would suggest
that the Lee 356 120 TC is more likely to work than some of the other
9mm designs.

Be sure your TC is done tight enough is the only thing that I can add.

Bill

[Bullwolf]

The Lee tumble lube 9mm RNL has a "Lip" formed by the top lube groove on the TL design. Loaded to "suggested" OAL's allows this section of the boolit to extend past the case mouth, and come in contact with, the chamber area "lip" where the boolits start contact with the rifling.

Hope I said that clearly, LOL!

I think Heavy Metal may have sussed out your problem.

The over all cartridge length is not cast in stone, and your gun will determine just what length it should be. Do realize however if you go with a shorter OAL, that pressure can increase quite quickly in 9mm, and be sure to work up from a safe starting load.

I also use that Lee TL356-124-2R boolit. I tumble lube and run it through a Lee .358 sizer die. When setting up that boolit for 9mm I use a loaded overall cartridge length of 1.10 that has fed well for me in all of my guns.





I worked up a load that reliably cycles my 9mm firearms at close to or under 5.2 grains of Unique. All of my 9mm pistols will chamber a .358 diameter boolit, so far. The Lee TL boolit and that load functions with no leading or hiccups in a wide variety of my 9mm pistols.

I've had pretty decent results using the Lee TL356-124-2R in my CZ75 clone.
A Tanfoglio TZ-75.



It's quite possible your seating a bit too far out for your gun and that's causing the problem. Or perhaps your particular gun just has a very tight chamber with hardly any leade or throat.

While I have not personally experienced this with a CZ-75 or a CZ clone, that does not mean it's not possible, and I definitely wouldn't rule it out.

I liked the image that ipijohn linked from the CZ forum, it's a nice graphic example of this.

Info from the CZ forum. http://www.czfirearms.us/index.php?topic=60696.0 One can try to explain this but the cartoon in the first post explains it all.

Try making up a few shorter OAL dummy cartridges and see if they plunk. If that works fine for you, reduce your powder charge and work the load up with the shorter OAL.

If I ended up with an abnormally short overall length that didn't want to feed well, I might try using a different boolit style like a TC (Truncated Cone) with that particular gun.






- Bullwolf

[W.R.Buchanan]

Kingman: I am amazed that someone didn't inquire as to this "LIP" you are talking about.

Where exactly is this "LIP."

Is it on the Feed Ramp? Is it at the mouth of the chamber? Is it at the front end of the chamber? You said it was shaving lead?

This sounds like a machining burr, and especially if it is at the front end of the chamber. If it is in fact there then the barrel either needs to have it removed or sent back to CZ to be fixed or replaced.

These guns are not noted for poor machining. They are not known to have odd sized barrels or tight chambers either, however minor errors can happen with any machined part and in this case as the chambering reamer's condition decays, it will eventually push a burr.

A picture of the "LIP" would be a really good thing to include in this post. We might be able to actually help then.

IF your loads are being assembled with normal OALs for boolits of common origin and charges which are prudent to the application, then something else is wrong.

This sounds like a mechanical problem, not a load problem.

Randy