The arrows that I have right now are CE Piledriver 350s. I was given a handful of the exact same arrow, same length, but they are 250s instead. I've never raised many questions about the spines and just let my bow shop take care of my setup. Since these arrows just kind of popped up in my possession I figured I would see if anyone has any knowledge they would like to share. Are they going to shoot the same? Or are there going to be fairly drastic differences between the two arrow types? I couldn't figure out a straightforward answer through my searches on the old google machine. I shoot a Bowtech Carbon Knight at #65 and a 29" draw length.