A similar thing happens with HBN (Hexagonal Boron Nitride) powder coated bullets. Bullets tumbled in HBN need MORE powder to get the same velocity as un coated bullets because they are so slippery. (yeah, counterintuitive, I know.)
But from a cold bore they give you the SAME point of impact as the rest of your shots! David Tubb sells both the powder and HBN coated bullets should you just want to they them without buying a tumbler and the HBN powder.
I suggest this approach with a "regular" chamber to get more accuracy and proven longer barrel life.
No, this is nothing like "Moly" coating. It is far superior for several reasons. Go to Tubb's site and read why.