RL-15 is pretty much interchangeable with Varget and H4895 in the 150, 155, 165, 168 gr bullets in a .308 Winchester.
That said, RL-15 will generally give me better accuracy than Varget, or is easier to dial in.
It is a little denser, so you can get more in the case, up to 47.0 grains with a 150-gr bullet, but you will probably see accuracy fall off as your approach that.
Varget is less temperature sensitive than RL-15, a consideration in match shooting and climates. The US military teams and snipers use RL-15 under the 168-gr Sierra and 175-gr.
46.3 grain RL-15, Federal brass, 210M primer and a 150 ballistic tip at 2.80 inch COAL duplicates the Federal Premium ammo, 2770 fps from a 24-inch barrel.