Re: PSIs Versus LUPs
Sorry, but there is no conversion factor for this, as it's not a linear transition. LUPs, or Lead Units of Pressure are still used in some applications, and are similar in nature to the CUP (Copper Units of Pressure) that was long used for most metallics. LUPs were generally used for shotguns, and other very low pressure applications that couldn't be accurately measured by the CUP method.
CUPs, because of the higher numbers involved, are often assumed to be translatable to PSI, but again, it's not linear, and these numbers can't be traslated like this. In some instances the same cartridge measured by both methods may show a higher CUP figure than it does PSI. Others within a different pressure range may show exactly the same numbers in both PSI and CUP, while in a different pressure range, others may show the PSI having a much higher figure than the equivalent load tested in CUP. Different measurement methods, different results, and no direct way to correlate the three other than on a case by case basis.