Spreadsheet for calculating chamber pressure

[Benchrest]

Has anyone here downloaded Close Focus Research's chamber pressure spreadsheet?

http://closefocusresearch.com/calculating-barrel-pressure-and-projectile-velocity-gun-systems

If so, thoughts?

Plugging in some pretty common 9mm weights / velocities yielded some interesting results (if I'm reading the barrel length correctly).

Kinda seems like a 'one size fits all' approach.

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[Benchrest]

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[jordanka16]

Interesting idea but there's too many variables I think for plain math to get it right. I plugged in some numbers for 9mm+p ammo and got pressures in 5.56 ranges, not quite right.

 

[Benchrest]

Yeah, I don't think it's factoring rise time / other variables.

Top published Power Pistol loads out of a 3" (according to how they measure) put pressures significantly above SAAMI.

Entered my 'warmer' PP load, ouch!

 

[jordanka16]

Yup, it seems to generally give numbers that are high, which I guess for safety's sake is a good thing. Mild loads seem to come up with numbers that are closer to measured levels.

 

[Benchrest]

1: When did they start using 'letters' in 'math'!
2: It seems from the equation below that only peak pressure is used, treating it as a constant.