SAAMI Pressure for 9mm

HankB · 01-31-2011, 08:28 PM

Pressure standards for most cartridges used to be measured in CUP - Copper Units of Pressure - which relied on measuring the deformation of a copper crusher that powder gasses had impinged upon, and comparing the measured amount of deformation with that found in a tareage table to determine pressure. (Shotguns used lead crushers to determine - you guessed it - lead units of pressure, or LUP.)

Current industry standard is to measure and list pressures in pounds per square inch (PSI) using piezo-electric transducers. The standard maximum average pressure for 9mm P is 35,000 PSI. The standard for "+P" is 38,500 PSI. There is no standard for "+P+" ammunition, but I have some from Remington and Winchester that is labeled "40,000 CUP."

What does 40,000 CUP correspond to in PSI? I don't know, but would guess it's close to 45,000 PSI. But that's ONLY a guess. Though CUP and PSI seem to roughly correspond to one another, there is no known universal formula for converting CUP to PSI.

Things are further complicated by the method of using piezo-electric transducers - I believe SAAMI and the European CIP do things a little bit differently.

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01-31-2011, 08:28 PM	#17
HankB New User Join Date: Apr 2007 Location: Central Texas Posts: 3 Thanks: 0 Thanked 0 Times in 0 Posts	Pressure standards for most cartridges used to be measured in CUP - Copper Units of Pressure - which relied on measuring the deformation of a copper crusher that powder gasses had impinged upon, and comparing the measured amount of deformation with that found in a tareage table to determine pressure. (Shotguns used lead crushers to determine - you guessed it - lead units of pressure, or LUP.) Current industry standard is to measure and list pressures in pounds per square inch (PSI) using piezo-electric transducers. The standard maximum average pressure for 9mm P is 35,000 PSI. The standard for "+P" is 38,500 PSI. There is no standard for "+P+" ammunition, but I have some from Remington and Winchester that is labeled "40,000 CUP." What does 40,000 CUP correspond to in PSI? I don't know, but would guess it's close to 45,000 PSI. But that's ONLY a guess. Though CUP and PSI seem to roughly correspond to one another, there is no known universal formula for converting CUP to PSI. Things are further complicated by the method of using piezo-electric transducers - I believe SAAMI and the European CIP do things a little bit differently.