Thread: Whats the difference

so I was trying to find a manual calculation I could do to work out spin drift and the JBM site came up on Google, anyway when you're on that trajectory page and write in all the crap there is the first part at the top where you choose your projectile. I went down until I found 168 Amax I saw the moly coat one under it too but under that there is the Litz. Whats the Litz one about?

Also if anyone could link me to a site or tell me the way to manually work out spin drift that'd be great.