Of the powders you listed, the 3100 will be the better of the two from my experiece.
However, both are on the fast end of the spectrum for the .300RUM.
I've gotten good accuacy, with lower velocities from IMR7828. 84.0gr produces just under 3,100fps for a "level 2" load roughly duplicating the .300WinMag. This load is accurate with a reduced level of recoil. the max load of 87.0g isn't as accurate, but comes real close to duplicating factory loads.
My favorite powder is Reloader 25. It gives factory duplication and is accurate as well. I use 92.5gr with a 180gr for 3,250fps. Fastest powder is Retumbo, and 100.0gr gives me over 3,350fps and reasonable accuracy. (my rifle isn't a tack driver, accurate is 1.25-1.5" for 3-shot groups. Not so accurate is over 2" at 100yds).
My go-too load however is some surplus .50BMG powder. It's WC-860, and was sold by Hodgdon as H870. My lot# is pulled down from .50BMG ammo, and has a little bit of extruded powder granules in it. It gives factory level velocities at 104.0gr and max's out at 107.0gr for 3,350fps with a 180gr bullet. At 104.0gr, I get near MOA accuracy from the 180gr Remington CorLokts at 3,275fps. I've taken two deer with this load, and the bullets didn't seperate at close range.
I saw some data that gave good accuracy with IMR4350 in a magazine article, but my rifle didn't like the powder. I believe the load was 75.0gr for about 3,100fps. Be sure to double check that load before working up to it.
(note:my barrel is 26" long. Some Remington's have 24" bbls and velocities are down about 125fps from my listed figures).