Greetings- I am looking for load data fot 7.62x25 TOK for use in CZ52 pistol.

I have bulleye, unique (and 2400 not a good choice?) and 85 gn jsp and 90gn JHP and .22 cal 45gr/308 sabot to load.


Thanks for any help in advance.

"Hornady 5th" 2000, "Our CZ52 test pistol was..both strong and .."
90 gr XTP, 11.8 gr:
a) 2400, 1500 fps
b) 14.2 gr H110, 1700 fps

"Sierra 4th" 1995, "..the Vz52 is an extremely strong pistol." "..Tokarevs, starting loads should shown should be considered maximum."

90 gr JHC, 6.6 gr Unique, 1500 fps

=======================================

I have tested allot of guns for strength, and the CZ52 is the only semi auto pistol I have found that is weaker than the brass. It also has the thinnest chamber I have seen. When I write to the author's of gun magazines or load books that repeat the error that the CZ52 is stronger than the Tokarev, I am typically told that they were just printing what they read elsewhere. There is never any interest in retraction or correction. Sierra's reaction it typical:

Quote:

---

Clark, Thanks for the information. We would be interested in some details if you have time to share them. Obviously Kevin (the author) was referring to the locking mechanisms and not the barrels but we certainly are interested in your findings. They may save someone the
experience you have had with these guns. Rich

---

I believe the error can be traced to the 1970 document:

Quote:

---

From the U. S. Army Foreign Science and Technology Center's publication titled "Small Arms Identification and Operation Guide - Eurasian Communist Countries", (FSTC-CW-07-03-70), page 211, Table XI, Cartridge Data and Color Codes, in reference to 7.62 x 25 mm pistol ball type P;

"Do not use Czechoslovak-made ammunition in TT-33 pistols."



--
A society that teaches evolution as fact will breed a generation of atheists that will destroy the society. It is Darwinian.

Clark- thanks for the data and the warning.

Can you further define what you mean exactly about the chamber being weaker than the brass?

Do you mean that you had a chamber failure occur but no brass failures- like a blown primer or cracked cases, indicating too much pressure?

With my revolver, I had one batch of reloads that had a few blown primers, I didnt get too spooked since they extracted normally and if the cylinder yielded to the pressure, the top strap of the frame would hold it in one piece.

With this semiauto, it looks like the slide could blow plum of the frame into my face if overloaded.

Thanks for the help
Brad

If I increase the powder charge .1 gr at a time, and examine each spent case carefully, with a semi auto, I expect to see a case bulge:

picture of case bulge in the shape of the feed ramp on a 7.62x25mm case



Or the primer would fall out: pic of primer fell out of 7.62x25mm case



That is the sort of thing that happens when I do an incremental overload work up in 25acp, 32acp, .380, 9x19mm, 9x23mm, 357 Sig, 40 S&W, 10mm, 45acp, and 7.62x25mm in a Tokarev.

But in a CZ52, the barrel splits before I an reach that point.

picture of split CZ52 barrel



My theory as to the reason the CZ52 is weaker than all other semi auto pistols I have tested, is that the bottom of the chamber is so thin where the space is milled out for the rollers:

picture of split CZ52 barrel with ruler next to break



A guy can blow up allot of revolvers looking for the same pressure signs. The Semi autos have weaker brass becuase of the extractor groove and becuase of the feed ramp. The semi autos get yanked out of the chamber even when cases are sticky [unless the extractor is removed for an experiment].

The revolvers do get sticky cases, and this pressure sign is all I get.



Old post from a guy at JPL calculating sticky cases for 357 mag

Clark;

That is very interesting information- I appreciate you sharing the barrel warning.

To be sure I correctly understand the data you posted on the prior post for 7.62x25 in a CZ 52:

90 gr XTP, 11.8 gr 2400, 1500 fps
and
90 gr JHC, 6.6 gr Unique, 1500 fps

are both MAX loads that I should work up to if no problems arise(not starting loads).

I sure dont want to blow out my chamber !

Thanks
Be Safe
Brad

Yes, those are max load published for the CZ52 and they are conservative loads.



The HOT published CZ52 loads are the Accurate Arms loads developed in 2000 by Ted Curtis at 42 kcup. Those loads are now missing from the AA web site, but are still around in the AA load book.



11.7 gr AA#9 makes a 110 gr FMJ bullet go 1688 fps in a CZ52 "Accurate load book #2" 42,000 cup.



The really hot loads I do in a Polish or Chineese Tokarev pistol are [and I have tried allot of powders without benifit of published loads]:



a) 9 gr Power Pistol, Starline, wsp, 1.316", 110 gr HNDY FMJ, ok

b) 10 gr Power Pistol, Starline, wsp, 1.316", 110 gr HNDY FMJ, primer falls out, +.015" ext grv

c) 10 gr Power Pistol, S&B primed, 1.316", 110 gr HNDY FMJ, ok, no ext groove change measureable

Clark,

Thanks for the help. One more question, how many rounds do you typically test for a given recipe before you can consider it safe and add the next .1gn of powder?

I am thinking I will load maybe 16 (two mag fulls) shoot and evaluate them, then move up .1 gn and repeat until I reach or nearly reach the max load.

Does 16 sound like a reasonable number?

Oh another question, do you know what the pressure chambers should be for a max load? I think you had referred to a 42,000 cup but it was for loads you believed were too hot.

I was curious about that- I am wanting to evaluate 22 caliber cartridges that are about the same dimensions and pressure ratings as the 7.62x25 tok - I am going to reload sabots in it later.

Thanks

Brad

If I were you, I would not do any experimenting with CZ52s.

Just follow the published loads, like you would with any gun that is so weak it will split before the brass flows.



When I started out overloading 5 years ago, I used a trigger string. I worked up at .1 gr. per increment and one case per increment, starting at the start load, and looking at every case with a microscope before proceeding.

I found out that CZ52s with thin chambers and revolvers with thin chambers can spit before there is any pressure sign with the brass.



Now days, on guns that are stronger than the brass, like Tokarev pistols and '98 Mauser rifles, I work up at 1 gr. per step and one round per step.

I hold the gun in my hands.

When I reach trouble, I work back down and note the threshold level.

For useful loads, I like 6% powder charge margin between me and the first hint of problems [like .001" extractor groove growth or a slight feed ramp case bulge].



Ted Curtis tested Tokarev ammo from all over Eastern Europe and it was all about 42 kcup [even the Czeck ammo] exept Russian, which was lower. He then worked up loads with AA powder for CZ52s only. [the logic escapes me]



I don't work in pressures, I work in % powder below trouble.



--

A society that teaches evolution as fact will breed a generation of atheists that will destroy the society. It is Darwinian.