I am really enjoying this thread, and learning a lot about ballistics in the process. It is also quite entertaining keeping me checking the thread quite regularly throughout the day. I would also be very interested in joining the "challenge" if it ever happens.
Here is a link that directs you to the Sierra Bullets website and an article that describes the difference between CUP and PSI. There is no conversion factor between the two. This article quite nicely explains how the two different numbers are achieved
https://sierrabullets.wordpress.com/...ers-institute/