A. There is no mathematics formula for the conversion of LUP/CUP to PSI or visa versa. PSI is directly measured by a conformal piezo electric force transducer. This allows for a direct reading of the pressure. LUP/CUP depend on piercing the case and allowing the generated gas to compress a crusher. The deformation of the crusher determines the LUP/CUP value. This is an indirect method of measurement that is less accurate at both the high end of the pressure range and the low end of the pressure range. Both PSI and LUP/CUP are accepted methods of measuring pressure in cartridges. All Hodgdon data conforms to SAAMI specifications unless noted otherwise in the data.