If someone could confirm that CUP is a constant, that would be great since limiting CUP is a primary concern in a Krag. Going back to the Loadbook to compare the test criteria, the only differences I see noted between the IMR testing and the Nosler testing is the primers and the overall cartridge length.  IMR used Winchester LR primers whereas Nosler used CCI 200 primers. IMR used an OAL of 3.000” whereas Nosler appears to have used 3.089”. IMR data shows a “C” after the powder load also (means compressed?). If the Winchester primers are hotter and the IMR load density was higher or even compressed, maybe that is why the IMR data for a 25.5” barrel is similar to Nosler data for a 30”?