When I shoot a ladder test I try to shoot 500 yards. I shoot 1 round with lowest powder charge and (for me) increase the charge .5 grs. untail I reach max load. I also seat the bullet to touch the lands in this test as this is where max pressure will be. I am looking for one thing - closest vertical group of shots with a wide range of powder charges. There is usually 2 of these groups. For me this tells me how the harmonics of my barrel are working with a wider range of powder charges. My 260 right now shows a group of 5 shots less than 2" with powder charges from 39.5 to 41.5.