Tried V V N-560 powder today, 87 - 92 grains in one grain increments (don't try this at home). Velocity 2880, 2891, 2937, 2973, 3010 and 3027. The highest 3 loads produced flyers (they were VERY FAST flyers but flyers none-the-less).
I believe I'll load 88 grain of V V N-560 and try hunting, 2900 FPS is fine for now and I'll try Retumbo once I can get some.
The 338RUM is still a fine shooter and there are folks wanting it all the time (traded it to a buddy of mine). Here's a picture of the thing.
(It's the bottom rifle.)