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I bought a 30 Mauser reamer because it is cheaper than a 7.62x25mm Tokarev reamer.
I bought it use up Tokarev ammo in a rifle I built.

The dimensions in the books for the two cartridges are closer than typical tolerances on SAAMI registration of chambers or cartridges.

Many books will say that the 30 Mauser is lower pressure than the Tokarev cartridge and so one should not shoot Tokarev ammo in a 96 Mauser. As I like to point out, the 96 Mauser is built stronger than the CZ52, and the Tokarev is stronger still. When I contact book authors, the errors seem to trace back to a US army publication in 1971.

The cause the erratic variation in which CZ52 blows up, I have now traced back to a wide variation in RC hardness of CZ52 barrels.
 

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I got a 30 Mauser reamer directly from Clymer for $80 5 years ago.
It does not seem to be a standard reamer any more.
The wild cat price is higher, but the reamer can always be had.


I bought the broomhandle just to verify that it is stronger than the CZ52.
I can work up to level that blew up one CZ52, but the primer pierces with the large firing pin hole. The chamber and barrel are also looser than the CZ52, so the experiment lacks control.

The broomhandle looks stronger.

A CZ52 blew up at the Issaquah range where I shoot, and someone was injured.
That was with surplus ammo.
The current crop of load book loads would not blow up a CZ52, but surplus ammo can blow up the CZ52s with soft barrels.
 

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I believe if barrels made of better steel and/or better heat treat could be had, then the CZ52 become stronger than the brass.

I cannot make barrels, but I can machine the outside. I could make CZ52 barrel from an annealed 4140 .308 barrel, heat treat it, and it should become safe like other semi auto pistols. Especially if the roller relief were a few thousands shallower, and a few thousands of roller were ground off.


Right now, the load book loads for Tokarev are as wimpy as any factory 30 Mauser load.
The danger for shooting CZ52 is surplus Tokarev ammo or overloaded handloads.
The Tokarevs can take overload work ups until the primers fall out.
 

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I remember testing between 2000 and 2005.
The CZ52 barrels were splitting.
The undercut for the rollers was too deep.
THe chamber was cut too tight.
The RC hardness was from 23 to 47. We tested after hours at the Jet Propulsion Laboratory in CA. A prestigious lab for guys too cheap to buy their own RC tester:)

The CZ52 chamber were so tight, I could put the barrel in a collet and use the chamber as FL resizing die for other pistols.
I remember people telling me I was crazy for saying Tokarevs are stronger than CZ52s, until enough CZ52s blew up with factory ammo. Then by 2005 the load books downgraded CZ52s and never upgraded Tokarevs. I was converting Tokarevs from 9x19mm to 9x23mmWin and getting more performance than others could with converted 1911s. I am still getting emails about 9x23 Tokarevs now after 15+ years.
 

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Any ideas on what signs to look for?
I can recall from 2005: There are two types of gun; Those that are stronger than the brass and those that are not. The guns stronger, I can incrementally work up until I see brass start to fail. If the whole brass case head fails there may be secondary failures, so the case must be checked carefully for small changes with each step. But if the gun is weaker than the brass, work ups have less useful meaning. One must avoid failure in a weak gun through large inaccurate folklore [published data]. CZ52s are weaker than the brass. Tokarevs are stronger than the brass. My single example C96 tests are inconclusive due to primer piercing due to firing pin to firing pin hole fit.

What does it all mean?
Don't work up a CZ52 looking for pressure sign on the brass.
Just use conservative published data.
 

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My only tests on Tokarev brass is that the S&B brass [pull down or reloaded] is stronger than the Starline brass. The only testing I have done on steel cases is 7.62x51 in an Ishapore, and that test was for accuracy.
Sorry.
 

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I have 100,000 posts on rec.guns, mostly in the 1990s.
In 1991, I went to work at Physio Control as a power supply design engineer to solve an EMI problem. There was a Spark workstation on my desk that had access to the usenet. Email took a week to get to my wife at Fluke, but once a day there was an update from rec.guns. Up until then I owned a 12 ga, a 30-06, and a 22, like my father did. My gun forum addiction lead to my gun buying addiction. By 1999 I started handloading, and blowing up guns was just like blowing up transistors when overload testing my power supply designs.
There are two rec.guns guys from Maryland; Ken Marsh the software engineer, and Magnum the professor of computer science and moderator.
 
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