RE: hogdons powder
H4831 has always been a good powder for the 270 Win. But the SC version would be better because you can get more of it into the case, and it meters better through a powder measure as well. I would use the SC version.It's performance is identical to H4831, just has smaller grains.
IMR 4831 is a bit faster, and it only comes with the big grains. It would work OK, but I prefer IMR 4350 in the 270Win. (Hodgdon now owns IMR as well.)