cartridge and chamber dimensions


September 12, 2009, 10:36 PM
i can find detailed drawings of the 45 acp and 45 colt cartridge and chambers for them, but what about the other pistol calibers namely 38/357, 38 sw, 41, 44?

id hope for drawings that show dimensions for the interior design so i can model them correctly with the correct mass to them for a computer to handle.

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September 13, 2009, 02:09 AM
Cartridge drawings with dimensions are here.
"...the correct mass..." The dimension of the chamber has nothing to do with the mass of the cartridge. Cartridge mass is neglible.
Game designing? A computer doesn't care about the mass of anything. There is no mass as far as the machine is concerned. It's only interested in what you tell it to do.

September 13, 2009, 09:47 PM
i want the interior dimensions so i can do a little pressure testing with CADD modeling software. id like to figure out rupture stress if i can get the right material info for the cartridge casing and compare it to established pressures.

September 13, 2009, 10:06 PM
Interesting. Chamber dimensions will be slightly different with every pistol. Just like a rifle chamber is slightly different. Has to do with tooling wearing a wee bit every time it's used. So will revolver cylinders. The finished dimension depends on the reamer used and how often it has been used.
These are the dimensions used in 4-D's reamers.
"...right material info for the cartridge casing..." Brass is an alloy, as I'm sure you know, doubt you'll be able to find the exact alloy though.

Jim Watson
September 14, 2009, 08:29 PM
Official SAAMI chamber and cartridge dimensions are shown in their technical publications at:

Cartridge brass is 70% copper, 30% zinc, but its strength depends on heat treatment and work hardening, case thickness varies in no simple fashion, and I fear there is no single number that will characterize it. The case does not contain the pressure anyhow, except in small "unsupported" areas where the brass is the thickest and the chamber or breech is cut away for functional reasons.

September 16, 2009, 11:09 PM
Any RCBS reloading manual will have saami spec drawings and measurements.

There are such things as 'universal receivers' that are used for pressure testing given loads. I've never seen one for sale, but occasionally a given make of rifle (say a Mauser kar98k) will have a 'proof version' come up for auction.

Jim K
September 16, 2009, 11:32 PM
The loading manuals give the average cartridge dimensions but, as Sunray says, both chamber and cartridge dimensions vary within a tolerance range.

The reason is that reamers wear, and reamers are used not only to chamber the barrel but to make the dies used to form cartridge cases. A new reamer starts out at the maximum (biggest) end of the tolerance range. As it dulls, it is sharpened. This goes on until it is past the minimum (smallest) end of the range, at which point it is discarded.
Some custom gun makers claim to use only reamers already at the small end so the chamber is "tight", supposedly ensuring greater accuracy. Since the reamers don't last long, one thing that is ensured is greater cost.


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