RE: Moly Coated Bullet
About the only conceivable reason to use moly bullets is if you are a competitive shooter who needs to fire 100+ rounds through a rifle on a match day and don't have time to clean in between. The moly reduces fouling and reduces drop off in accuracy from fouling. The downside is that its difficult to remove from a barrel and can cause corrosion by drawing moisture from the air.
There isn't a single good reason that I can think of to use moly in a hunting rifle.