I have an experience with RL19 being heat sensitive, while shooting in a .280 Rem. The first 2 shots were fine, (on a hot 90 deg+ day) and the third flattened the primer big time and the recoil was severe (relative to what it should have been). That is the only time and only powder I have ever experienced that "phenomenom" with. I really like H4831sc and can't find a better choice overall. I like H/IMR 4350 too, it shoots well but not with the velocity. IMR7828 is good in my gun. It fills the case and gets good velocity with 130,140 or 150's. I have loaded some 160gr Partitions at @2800 fps or so just for fun. I hunt here in Colorado and have shot muley's with a 140gr. Hornady BTSP with 4831sc pushing it to the high 2900's. At 100 yds it did the trick, however I found nothing left of the bullet inside on a broadside shot. I have been a Barnes X devotee for a while as well and like the ability to shoot at harder angles those bullets give me. I like an exit wound for some reason and the Barnes has never stayed in an animal and they fell just as quick or quicker.
As for more powders, try RL22 as I have had good velocity with that. I find accuracy is not determined by powder for the most part. I play with seating depth of the bullet and that gives much more consistent and definitive results than burning up lots of powder. Pick a powder that gives high velocity at good pressures, and play with seating depth .010 at a time.
Bonz.