Straight from Leupold in case anyone else is wondering.
The RX-1300I has bow mode, line of sight, and TBR modes. It is designed for the person who rifle and bow hunts. The RX-Fulldraw was designed for bow hunters. It is in bow mode the whole time till you range pass 175 yard. Once you go past 175 yards it goes to line of sight. It does not have angle compensation for rifles.