error in the rec.guns faq about CZ52s
Clark Magnuson
http://www.recguns.com/Sources/IIIC2f.html
" The CZ-52 uses a 8 round single stack mag. It utilizes a roller
locking system to safely use all sorts of Tok ammo, from less powerful
loads for the Tokarev pistol, to very powerful loads meant for this
handgun (Czech M48 round) and also for PPSh submachine guns."
When I destroyed two CZ52 pistols in 2000 with experimental handloaded
overloads, and then could not harm Tokarevs with much higher overloads,
I found the weak spot, the bottom of the CZ52 chamber was very thin,
[.058" CZ52, .125" Tokarev], because the underside had been milled out
to make room for the roller blocks. I began to question the premise that
the CZ52 is stronger commonly printed in books, magazines, ammo
manufacturers etc., though out the gun culture.
http://www.thehighroad.org/attachment.php?s=&postid=249178
This is what I now believe probably happened to get this error into the
gun culture:
1) In 1970 the US army published an account of the CZ52 pistol.
Knowing that:
a) The Russians had a TT-33 pistol designed in 1933 that Russian Tokarev
ammo loaded to 31 k c.u.p.
b) The Checks had a CZ52 was designed in 1952 and that Czech 7.62x25mm
Tokarev ammo was 42 k c.u.p.
c) The CZ52 has a roller block locking system.
> ...
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."
2) In March 2000, I got a Letter [as did many others, and the letter was
handed out at the shot show] from Ted Curtis ballistician at Accurate
Arms. Ted Curtis, a very old ballistician already was bald and had jowls
in his 1966 photo in "Speer 7". All the typos are Ted's:
"7.62 X 25 Tokarev ..
Due to the large number of handguns imported into the U.S. chambered
for the 7-62 x 25 Tokarev Accurate Arms has developed the following load
data for those shooters who wish to reload the little powerhouse. In
determining the appropriate pressure limit for our load data we tested
various military ammo from China, Russia, Austria Bulgaria and the
Czech Republic. Commercial ammo produced by Sellier & Bellot was also
tested. Based on these tests we arrived at a maximum pressure for our
lad data of 42,000 C.U.P. Only the single lot of Russian ammo was
significantly below this pressure averaging 31,000 C.U.P. The consistent
pressures between all other type sand manufactures was a welcome
surprise . Indeed, the fact that CZech ammo, made for the CZ-52 pistol,
produced the same pressure as that of the other countries was perhaps
the biggest surprise of the whole project. This in spite of the "tribal
lore" regarding this particular handgun and the ammo loaded for it
claiming that shooting Czech ammo in any other firearm so chambered will
causes spontaneous disassembly. The pressure data produced by the ammo
tested certainly doesn't support this theory.
[Ted presented some loads with AA#2, AA#5, and AA#9 that were at 42 k
c.u.p. and very high velocity]
...We feel that the maximum loads shown here are suitable for the CZ-52 so
long as the firearm is in good condition. Other models of foreign
handguns of a lessor quality should probably be loaded in a more
cautious manner. "
3) What I believe happened was that:
a) 1970 the army was not aware or did not realize the implication if
China, Poland, and Bulgaria were also producing 42 k c.u.p. Tokarev ammo
and it was for their domestically produced Tokarevs. The army's
technical writer working on the paper either did not have a CZ52 sample
in 1970 or was unwilling to do destructive tests, unwilling or unable to
do a mechanical strength analysis, or was distracted by the roller
locking mechanism.
b) If Czech ammo for CZ52s is 42 k.c.u.p. and is the same as 42 k
c.u.p. ammo China, Austria, Bulgaria, and Poland make for their
Tokarevs, the ammo being used does not imply the CZ52 is stronger.
c) When Ted measured the communist block Tokarev ammo, he realized
there was an error in the 'tribal lore', but he did not realize that his
data implied that the rational [ used infer the CZ52 was stronger than
the Tokarev] was gone. He then published his loads for "the CZ52 only".
d) When I notified Sierra [a very good company with a very good rifle
handload book] that their "CZ52 is stronger" line in their handgun load
book was wrong, I got a typical reaction, ~ "We are impressed with your
load data, but we were just printing what WE read."
e) When I notified GUNWORLD magazine that their line, "The CZ52 is
stronger" was in error, Jan Libourel wrote me that he was just ~"
printing what HE read".
f) When I posted on the internet that "The CZ52 is not stronger" I
got many negative reactions from CZ52 owners that missed the nuance
between [that CZ52 are not as strong as the Tokarev] and [that CZ52s
will blow up with factory ammo].
--
A society that teaches evolution as fact will breed a generation of atheists that will destroy the society. It is Darwinian.
-----------------------------------------------------------
Learn about rec.guns at http://www.recguns.com
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Clark Magnuson
overloads of their 2000 data.
In 2004 AA took the CZ52 load data off their web site.
Today I noticed they put NEW CZ52 data up that has been reduced from 42
k c.u.p. in the 2000 data to 35 k c.u.p. for 2004.
shey...@myrealbox.com
On Thu, 1 Jul 2004 00:39:42 +0000 (UTC) Clark Magnuson <c.magnuson@comcast
net> wrote:
>http://www.recguns.com/Sources/IIIC2f.html
<snip>
>When I destroyed two CZ52 pistols in 2000 with experimental handloaded
>overloads, and then could not harm Tokarevs with much higher overloads,
>I found the weak spot, the bottom of the CZ52 chamber was very thin,
>[.058" CZ52, .125" Tokarev], because the underside had been milled out
>to make room for the roller blocks. I began to question the premise that
<snip>
Have you conducted any experiments and tests using heavy loads with
any of the popular after-market barrels for the CZ52 chambered for
the 9mm Luger caliber?
I have fired a couple of magazines of 9mm Luger 115 grain JHP
+P loads through mine. The ammunition was manufactured by Magtech.
This ammunition functioned and cycled and performed just fine, and
without causing any damage to the barrel or any other part of the
gun. I found it just as accurate as 115 grain FMJ regular loads
and more accurate than 124 grain FMJ regular loads.
Also I found that I had to file a little bit of metal off of the
bottom hook of the extractor in order to make any of 9mm ammo feed
properly. At "makarov.com" you will find that remedy suggested
for those who experience feeding problems when using a 9mm barrel
in a CZ52. It worked for me.
Has anybody else here fired heavy loads in a CZ52 having one of the
after-market 9mm Luger barrels?
Sam Heywood
--
NTReader v0.32w(O)/Beta (Registered) in conjunction with Net-Tamer.
KDraut
overloads
Why don't you post your handloads for the rest of us to see?
Kirk
Clark Magnuson
7.62x25mm Tokarev 110 gr. FMJ, 1.3", AA#9:
a) AA 2004 published load 8.5 gr. 1248 fps, 34,270 cup
b) AA 2000 published load 11.7 gr., 1688 fps, 41,800 cup
c) My CZ52 chamber failure 13.7 gr.
d) My primer pocket failure in S&B brass in my stronger Tokarev pistol
15.3 gr. = ~ 69,092 cup
If the 7.62x25mm Tokarev round were registered with SAAMI at 42 kcup
[the average pressure of Eastern block Tokarev ammo], then the SAAMI
proof pressures would then be between 54,600 and 58,800 cup.
It does not take much imagination upon reading my data to see the CZ52
may NOT pass a SAAMI proof test [if someone registered the cartridge in
the USA] for Tokarev ammo, but the Tokarev WILL pass.
In the word typical of printed material on this subject, "Sierra 50th
Anniversary Handgun Reloading Manual" 1995, ".roller block ..the vz52 is
an extremely strong pistol. Reloads developed for pistols using less
robust locking systems must be reduced drastically for safety reasons.
In recoil operated pistols such as the Tokarev, starting loads should be
considered maximum." The loads in the Sierra manual [6.6 gr. Unique , 90
gr. = ~ 30 kpsi] are lower pressure than old Lyman loads for the 30
Mauser/7.62x25mm Tokarev [6.6 gr. Unique, 93 gr.], so there is adequate
safety margin in Sierra manual, and merely misinformation.
The only published load data that was up to Eastern block Tokarev
performance was the AA 2000 to early 2004 data.
All other published handloading data available to Americans is low
pressure. Even Vihtavuori is about 30 kpsi.
So there would be four problems:
1) The safety margin when shooting CZ52s [ with Check, Polish,
Austrian, Bulgarian, or Chinese ammo, or Accurate Arms load book,
pamphlet, and web site pdf download able data 2000 to early 2004
handloads ] is below American standards.
2) It is written many places that the CZ52 is strong and that is wrong.
3) It is written many places that the CZ52 is stronger than the Tokarev,
and that is wrong.
4) Those with Tokarevs are told in the AA 2000 to early 2004 data, "for
CZ52s only" and this represents a missed opportunity to take advantage a
the great potential of the Tokarev pistol.
I am open to how to resolve these discrepancies.