I do not recall the name of the person that conducted this experiment. And maybe my partner in crime cam assist on this, but he did a incremental test using a crimp die, and with different torques applied to the crimp, he got different , but consistent , velocities, and es readings. I've ran into the same thing when my adjustment slipped, or if I didnt use it, because I forgot it was part of my set up. I'll argue that neck tension definitely affects the overall performance of any round. Said again, consistency is is the key word here.