These are my results, I am shooting a sendero 300RUM and tried many different bullets and powder.
I decided on the 210gr Bergers
Bergers max loads with retumbo are 92gr @ 3035fps and their max load with H1000 is 91.6gr @ 3038
with retumbo at 92gr I was getting between 2979-3033 fps
With H1000 at 92gr I was getting 3011-3031fps
I have went up as high as 96gr retumbo with no high pressure signs and was getting 3120-3156fps
and with H1000 I went up as high as 94gr at 3093-3128fps.
I have also used RE22, RE25 and IMR7828SSC and tried Ramshot magnum and it, the ramshot magnum was the worst for high pressure and low velocities. I am going to stick with Retumbo, mainly because I have like 9lbs of it. Oh and I did also try hogdon US869-very temp sensitive, not impressed.