I traded for a .300 Win. Mag. Encore this past Saturday. My dies aren't here yet, but so far the standard 150 grain loads from Remington, Winchester, and Federal all hold at or below 1.5" ( these are not the ones with premium bullets).
If I allow the barrel to cool between groups, they stay close to 1.0".
I was concerned about recoil, but it's not a a lot worse than my 7x57 Ruger with warmer loads.