That is like the pressure rating calculation of pipe.

If there is interest, and I don't get kicked off Beartooth, I will post other examples of gun strength calculations, like the section modulus of the breech of a break action.

The thin wall hoop stress is directly devirable:

The inside diameter times the pressure is the force, and the thickness

of two walls are in tension, hence:

Steel stress = [ID][P]/[[2][wall thickness]]

When the walls are thin, Lame's Formula gives the same answer, but as

the walls get thicker, Lame's

formula gives an increasingly greater stress.

I got Lame's formula from "Mechanics of Materials" by Laurson and Cox,

1938 Wiley and Sons.

The derivation was first done the the French mathematician, Lame, 500

years ago. It is a difficult derivation.

If the barrel is thick, read an two inches further down my post to Lame's formula:

"Hoop stress for barrels with thick walls and high accuracy we need

Lame's formula for maximum stress in a thick walled cylinder subject to

internal pressure:

S=P(r2 squared +r1 squared)/(r2 squared - r1 squared)

Where S is the stress in psi of tension

P is the chamber pressure in psi

r1 is radius of the chamber or bore in inches

r2 is radius of the barrel [center to outside] in inches"

How to tell which can handle more pressure: CZ52 or Tokarev:

Measure the OD of the barrel in a CZ52 at the chamber:.590"

Measure the OD of the barrel in a Tokarev at the chamber:.640"

Measure the OD of the barrel in a CZ52 on the barrel:.468"

Measure the OD of the barrel in a Tokarev on the barrel:.494"

The Chamber ID is .390" and the grooves ID is .308" for the 7.62x25mm

Tokarev cartridge.

This makes the walls in the chamber of a CZ52 .1" thick

This makes the walls in the chamber of a Tokarev .125" thick

This makes the walls in the barrel of a CZ52 .08" thick

This makes the walls in the barrel of a Tokarev .093" thick

The formula for thin wall hoop stress is S=[chamber

Pressure][ID]/2[thickness of walls]

Assume 4140 steel heat treated.

If heat commercially treated and quenched 4140 steel has an ultimate

maximum tension yield strength of 180ksi,

http://et.nmsu.edu/~etti/winter99/manufacturing/kollmer/kollmer.html

Then the max chamber pressure for a CZ52 may be calculated:

Pmax[CZ52]ch = S[2][thickness or walls]/[ID]= 180ksi

[2][.1"]/.390"=92,000 psi

Pmax[Tok]ch= 180ksi[2][.125"]/.39"= 115,000 psi

This must be added to the pressure capacity of the brass:

Pbrass = S[2][thickness or walls]/[ID]= 66ksi [2][.035]/[.39

-(2).035]=14kpsi

The CZ52 chamber would then fail at 106,000 psi

The Tokarev chamber would then fail at 129,000 psi

Pmax[CZ52]barrel= S[2][thickness or walls]/[ID]=

180ksi[2][.08"]/.308"=94kpsi

Pmax[Tok]barrel= S[2][thickness or walls]/[ID]= 180ksi[2][.093"]/.308"=

109kpsi

It looks like the barrels are weaker than the chambers.

It looks like the CZ52s are weaker than the Tokarevs.