Using a bullet comparator and OAL gage

I'm a little bit confused about using the bullet comparator with the OAL. I'm using a Hornady OAL gage with the proper casing for a 30.06. I insert the bullet in the case and then both into the chamber and push on the gage until it touches the lands. I lock the gage in place and remove the entire group from the rifle.I attach the bullet comparator to the caliper and with the base of the casing on one end of the caliper measure the length of all three, bullet, casing and comparator. This is where I'm stuck. I need the length of the casing and the length of the bullet from the case to the ogive of the bullet. How do I find that? I want to find that length and subtract .005".

I finally figured it out!