Bullseye in the CZ52

[Outpost75]

I've recently been fooling with the 7.62x25 in a CZ52.

The loads in the Lyman Cast Bullet Handbook would not cycle my pistol.

I ended up using 5.5 grains of Bullseye with the 88-grain NEI No.82 flatnosed bullet for 1346 fps, and 6 grains of Bullseye with Norma 93-grain softpoints at 1490 fps, all using Starline cases and Federal 200 primers. Accuracy is better than PPU ball, which gave 1394 fps.

[9.3X62AL]

AA-7 is THE powder for the 7.62 x 25. Start at 7.0 grains with either bullet, and go north from there. The CZ-52 is far more tolerant of pressure than is the Tokarev TT-30/33. 1490 FPS with the 93 grainer is just hitting the CZ-52's stride, so to speak. I've used same/similar weights of BE with Lyman #313249 and the Lee 100 grain RN; the pistol really wants to shoot well, and AA-7 improves accuracy and shrinks SDs over BE.

[Three44s]

HS-6 worked nicely if I was not out to set the world on fire.

2400 was very accurate and regulated right with the sights.


Three 44s

[Three44s]

HS-6 worked nicely if I was not out to set the world on fire.

2400 was very accurate and regulated right with the sights.


Three 44s

[JHeath]

The CZ-52 is far more tolerant of pressure than is the Tokarev TT-30/33. 1490 FPS with the 93 grainer is just hitting the CZ-52's stride, so to speak.

Clark "The Destroyer" Magnuson kb'ed two CZ52s by splitting the barrels, but could not kb a Tokarev even with egregious overloads. He got flamed a lot for posting about this, the threads make for great reading. He also re-chambered 9mm Toks for 9x23 and double-compressed massive overcharges in those.

Apparently the CZ's roller locking mechanism appears strong, but the barrels have a thin spot at the roller recess cut, and the heat-treating is erratic. In addition to destruction testing, Clark did a hoop-stress analysis, Rockwell hardness testing, etc.

This does not seem to be a problem with reasonable loads in the CZ.

The Toks appear crude but are robust.

Clark's interest (and mine) is in the failure mode and safety margin. I do acrobatic rigging for a living. We do not rely on published "allowable loads" for hardware. We work backward from ultimate loads to our own design factors. So I relate to Clark's MO of doing load work-ups way past the published max and establishing the failure mode.

According to Clark, almost any auto pistol will show pressure signs at the case, then pierced primers, then case blowouts, before a catastrophic kb. What he found with the CZ52 was that the first sign of trouble was a catastrophic split barrel, and that the reputed strength of the CZ was based on erroneous assumptions, based partly on confusion about Com-bloc ammo pressures.

I don't want to rain on anbody's parade. If you do not overload your CZ52 you will probably have a lifetime of healthy fun. You should be wearing safety glasses anyway.

My nervousness about failure modes carries over from rigging. I would rather rig people with a carabiner that shows signs of yielding as it reaches its limit, than a theoretically stronger one that lets go without warning.

Assuming your self-image is not anchored on CZ52 ownership, you should look up Clark's posts, they're pretty entertaining. People got their feathers ruffled, but he was just doing basic science.

[9.3X62AL]

J Heath--you are reading far more into my statement than what is there. I don't venture into Clark Country with my firearms; my references are only to relative published data for the 7.62 x 25 as seen in the Hornady Reloading Manual, which provides data that ventures into the 1800 FPS realm for their j-words in the CZ-52. Most other references limit 86 grain-class bullets to the 1400 FPS level in this caliber.

As is often the case on this site, I again regret having said anything concerning my loading and shooting activities. I assure you that my self-image is in no way wrapped up in milsurp pistol ownership, and I find your smarmy remark insulting and demeaning. I am familiar with Clark's body of work, and find it fascinating--but his is not a road I care to tread personally.

[Outpost75]

I've read Clark's rantings, and my mentor, the late Dr. Robert L. McCoy, PhD, of the Combat Systems Test Activity at Aberdeen Proving Ground, wouldn't have allowed him to make the coffee. Sorry, wrong answer.

The 6 grain Bullseye load with Norma 93 grain .307" SP or FMJ is about 20% above published data for the .30 Mauser M96 Broomhandle. I have alot of experience loading for those and have done so for over 50 years. Bullseye was always the powder of choice for me because it gave the desired velocity with the lowest charge weight. Bullseye is the only pistol powder I use or need. It took me years to use up all the odds and ends of other powders I had accumulated over the years, giving much of it away, before I figured this out. I have no interest in other powders because all I want is an accurate load which safely cycles the pistol and does not put the brass into low earth orbit. I do not need to feel radiant heat from the muzzle flash against my cheeks to evaluate whether the load is any good.

[rattletrap1970]

I use a 311316 (112gr) boolit (.308 sizer), 4.6 gr of Scot 453 and seat to 1.340 (COAL).
In my CZ52 they shoot very accurately and slower than factory ammo. I will chrono them over my vacation.
I haven't tried Bullseye yet.

[Who's this Guy ?]

I have read Clark's testing he has done on both the CZ52 and the Tok and find it interesting. I was always a believer (until I read his tests)in the strength of the roller design of the CZ going back to what was written in the early 90's and some testing (firing and evaluation) that was done by the Late Charles Karwan who reportedly tested factory Surplus Czech ammo and chronographed loads into the 1600-1700 fps. That and the belief in the roller locking mechanism superiority I am sure contributed to the CZ52 having a reputation of action and design strength. I for one would not push the CZ52 design into the red zone and play it safe.

[JHeath]

J Heath--you are reading far more into my statement than what is there. I don't venture into Clark Country with my firearms; my references are only to relative published data for the 7.62 x 25 as seen in the Hornady Reloading Manual, which provides data that ventures into the 1800 FPS realm for their j-words in the CZ-52. Most other references limit 86 grain-class bullets to the 1400 FPS level in this caliber.

As is often the case on this site, I again regret having said anything concerning my loading and shooting activities. I assure you that my self-image is in no way wrapped up in milsurp pistol ownership, and I find your smarmy remark insulting and demeaning. I am familiar with Clark's body of work, and find it fascinating--but his is not a road I care to tread personally.


J Heath--you are reading far more into my statement than what is there. I don't venture into Clark Country with my firearms; my references are only to relative published data for the 7.62 x 25 as seen in the Hornady Reloading Manual, which provides data that ventures into the 1800 FPS realm for their j-words in the CZ-52. Most other references limit 86 grain-class bullets to the 1400 FPS level in this caliber.

As is often the case on this site, I again regret having said anything concerning my loading and shooting activities. I assure you that my self-image is in no way wrapped up in milsurp pistol ownership, and I find your smarmy remark insulting and demeaning. I am familiar with Clark's body of work, and find it fascinating--but his is not a road I care to tread personally.

9.3x62AL:

I apologize for having offended you. My remark was not intended to be smarmy. It was intended to head off a problem I saw many times before. You are clearly too seasoned to be ego-invested in a pistol model, my remark was just a boiler-plate disclaimer for a problem that I saw too many times to ignore. I regret I phrased it in a way that could be misunderstood.

I read many threads, spanning over years, wherein Clark reported his experiences with CZ52s, and contradicted people's beliefs about the relative strength of the two pistols.

Invariably, other posters became very offended, not because Clark said anything to insult them, but because over the course of the threads they allowed themselves to become personally invested in what should be a simple technical issue. This applied not just to the OP of those threads, but to many others.

With regard to the validity of Clark's tests, it continually suprises me that people find it so counter-intuitive. That seems to be happening here again.

The value is not that his overloads might somehow be a practical option. The point is in discovering the failure point, and more importantly the failure mode. P.O. Ackley did much the same thing. The strength of the Arisaka is interesting. Brownell reporting that he never blew up a Ruger No. 1 in testing is interesting. I have no practical interest in overloading those actions.

To give a real-world example, I invented a splice for high-tech rope. I was using it in 28,000lb rope. I did not know the efficiency of the splice, but knew it was significantly below 100%. But my design factors were so high I was not worried about it.

Still, I was gratified that the rope manufacturer decided to test my splice. He found it was 84% efficient. In my application, it would fail at 23,500lbs.

The manufacturer was aware that I was using his rope with 1,500lb tensioners. Thus he established that I had a 15:1 design factor. This was valuable enough for me to note and write down. But it had no effect on what I was doing.

Now, should I fault the manufacturer for needlessly destruction-testing my splice? Should I disparage him for being so silly to load a system to over 15 times its intended stress? Should I be insulted, as though he insinuated that I might be doing something unsafe?

Of course not.

With guns, we are dealing with unknown safety margins on the order of 1.5 or 2:1. Those are relatively low in engineering terms. The 7.62x25 is designed for what pressure? We do not really know. Around 45,000cup maybe.

And the CZ52 is designed to fail at what pressure? We do not know. Perhaps around 60,000 - 70,000cup.

And what is the designed failure mode of a given pistol?

I can tell you the failure mode of rigging components. It's basic information for people doing my kind of work.

These are legitimate questions even though I do not want to load a 7.62x25 to 2200fps or whatever preposterous velocity one might achieve with proof loads.

So why does another poster feel gratified by disparaging Clark with the "coffee" remark? Clark has done us a favor; just as the rope manufacturer did me a favor, although it had no practical effect on what I was doing.

And why say that Clark's work is irrelevant, because we are not loading "that hot"? Without determining the failure point and mode, we cannot know what "hot" means.

An aircraft manufacturer can tell you the failure point and mode of a wing. He will have done a combination of calculations and possibly destructive tests.

A small-shop furniture maker building a chair goes with his gut. It's an ordinary chair, he does not expect a 500lb person to sit in it. Will it support a 200lb person? Of course. 300lb person? Probably, it should. But at some point it will fail. The craftsman does not do a full structural analysis and destructive testing.

Is a tube containing 40,000lb pressure bursts in front of your face critical like an airplane wing? Or is it more like a wooden chair?

Clark noticed that the Accurate Arms loading manual assumed that the CZ52 could take very high pressures. This was not based on scientifically-derived information, it was an assumption. It was wooden-chair science, not airplane science, but it made it into a loading manual.

I find it wonderous that people disparage and insult Clark for asking interesting questions, gathering information, and sharing it. He has not taken anything from anybody. He has given, freely. Yet people get judgmental and even upset by him doing it, and by me mentioning it.

But that is not the nature of my having offended 9x3x62AL, which is due to my infelicitous but well-intentioned remark, for which I again beg his pardon.

[9.3X62AL]

That is very decent of you, sir--and I respectfully withdraw my comments made above.

Clark's intrepidity causes a number of responses, some of them none too complimentary. I didn't and don't value-judge his pursuits; his interests are not my own, my interests might even run counter to his--to NOT test to failure any firearms I own. I can't afford to blow things up, it strikes me as wasteful. Other hobbyists have divergent interests, and it isn't my place to question their motives.

I'm not well-founded in the physical sciences, and for that reason limit virtually all of my loading to tested data from reputable sources. The CZ-52 was my third pistol example chambered in 7.62 x 25/30 Mauser--the first being a rebuilt Mauser C-96, and the second a ChiCom Type 54 Tokarev variant. I limit the Broomhandle to 1200 FPS/90 grain bullets--the Tokarev to 1400 FPS--and the CZ-52 has run about 100 rounds at 1550-1600 FPS. The great balance of the CZ-52's shooting gets done with Tok-level loads, though. The CZ-52's design criteria spec'ed 85 grain bullets at 1700 FPS, though I cannot recall the source(s) of that information. My lasting impression is that when the CZ-52 will function reliably (and quite loudly) with 85 grain bullets at 1300 FPS, little is gained by running the pistol at red-line Just Because.

[MtGun44]

Given the ballistics of the cartridge, I would lean for a slower powder, say Unique or
slower. The HS6 and AA7 sounds pretty right to me. I have one, but have only shot
factory ammo in it - and rarely see a case again!

Bill

[JHeath]

Given the ballistics of the cartridge, I would lean for a slower powder, say Unique or
slower. The HS6 and AA7 sounds pretty right to me. I have one, but have only shot
factory ammo in it - and rarely see a case again!

Bill

I assume you are right about the slower powder. Clark said the most "power" (whatever that means! he gauges it by felt recoil) was with Power Pistol, which seems to have an almost variable speed depending on how much is used. I need to learn more about that; sounds like the more pressure it has early in the burn, the more it acts like a slow-burning powder. That was interesting because he was loading 110gr J-words, and I want to load 115gr boolits. I like the sectional density, and the idea of using the same weight projectile as a 9mm but smaller diameter and higher velocity.

But the OP's inquiry about Bullseye and 9.3x62AL's observations have me very interested, because my ears are bad and I hope to live longer and still talk to my wife, and listen too. This scores me points. She knows when I am faking it and then I lose points, so hearing has value.

Reducing muzzle pressure with faster powder like Bullseye sounds good, but I still want to shoot 115s, which may not be compatible. I will have to compromise on velocity.

[Outpost75]

Duplicate post deleted.

[Outpost75]

FWIW I have not gotten good accuracy with cast bullets over about 90 grains because their bases protrude below the neck, into the powder space, and there is risk of bullet base upset creating a "nail head effect" in which the upset base locks against the shoulder angle and the bullet cannot squeeze down again through the neck.

This condition has been thoroughly investigated in 5.56mm M856 tracer ammunition used in the M249 SAW and is the reason the NATO chamber has a "Vom Hoffe style" 11 degree, 30 minute blend transitioning from the neck base into the 23 degree shoulder.

I have also investigated similar blowups in. 243 Winchester and 6.5x55 ammunition when the bullet base was below the neck and there was airspace in the case, such that the powder plug upon ignition would strike the bullet base and upset it.

My advice is DO NOT use bullets in the 7.62x25 which protrude significantly below the neck.

[JHeath]

FWIW I have not gotten good accuracy with cast bullets over about 90 grains because their bases protrude below the neck, into the powder space, and there is risk of bullet base upset creating a "nail head effect" in which the upset base locks against the shoulder angle and the bullet cannot squeeze down again through the neck.

This condition has been thoroughly investigated in 5.56mm M856 tracer ammunition used in the M249 SAW and is the reason the NATO chamber has a "Vom Hoffe style" 11 degree, 30 minute blend transitioning from the neck base into the 23 degree shoulder.

I have also investigated similar blowups in. 243 Winchester and 6.5x55 ammunition when the bullet base was below the neck and there was airspace in the case, such that the powder plug upon ignition would strike the bullet base and upset it.

My advice is DO NOT use bullets in the 7.62x25 which protrude significantly below the neck.

Thanks. I knew nothing about this and will look into it. I think some of the shorty AR cartridges, Whisper etc are using long bullets that extend below the case neck. I have heard debates about whether gas checks can safely be positioned below case necks. I do not recall hearing of any of the above blowing up a gun, but imagined there must be some limit short of seating a bullet base against the flash hole . . .

Lighter projectiles with Bullseye may suit my purposes better anyway, or some of my purposes. But then what do I do with this 311316? Maybe buy that .32-20 Blackhawk out from under the guy on the other thread . . .

[Outpost75]

When GCs are positioned below the neck you can get gas escaping past the bullet and up the case neck and throat, which erodes the heel between the GC and bottom band. Having this gap packed with hard bullet lubricant tends to mitigate against this, and it seems to help when you have a nominal caseful of powder which is relatively slow-burning for the cartridge type, as the bullet starts to move up into the neck before full pressure and flame temperature is reached.

If no more than the GC itself is below the neck I am not inclined to worry much about it. The key is to see how well it shoots, as I Col. E.H. Harrison always said that "Accurate cast bullet loads are safe!" Therein lies the clue...

[dtknowles]

I did not see a question mark in the OP. When I reloaded for my CZ-52 I used Red Dot, 5.5 gr. got a 90 gr. LRN to 1400 fps. 6.5 gr. pushed a 60 gr. JHP to more than 1700 fps and I shot 45 gr. JSP in sabots using 7.5 gr. that were more than 2000 fps. With all these loads it never seemed like I was pushing things. That was really all just for experimental fun as I almost always shoot it with corrosive mil-surp that has a 90 gr. FMJ that clocks at 1400 fps. My bullets, my technique, my chrono, you mileage may vary.

Tim

[destrux]

I have only tried one load for my CZ52 so far, but it works so I don't plan to change it.

71gr jacketed bullets (.312" for .32ACP) resized to .309", OAL of 1.275", over 6.5gr Unique. Quikload shows 26,764psi and 1,519fps (max pressure is listed as 34,809 Piezo CIP). It operates my gun as well as factory ammo, doesn't seem to sling the brass as far, but still at least ten feet away. Accuracy is good. It is difficult to seat the bullets straight, and I did have to modify my Lee seater die to seat them.

I'd get a mold for this thing, but with brass being in such short supply I rarely shoot it.

[Outpost75]

Accurate, NEI and NOE have suitable molds. I'm using a shortened 88-grain version of NEI #82 which I also use in. 32 ACP and ..32 S&W Long.