Re: RL-33 Load Data
I see you are in the same fix I was with my various chamberings when I got my hands on some of the first RL-33 in the country.
I used it in:
6mm-284 with the 105 berger match hybrid target
300 RUM with 230 gr Berger match hybrid target
7mm-375 Ruger with 180 gr Berger match hybrid target
257 Weatherby with 110 accubonds
I believe a good place to start is to begin load development with a near max charge of Retumbo, suggested my Hodgdon, for each of your cartridges.
I just looked up the 338 RUM with a 250 gr bullet on Hodgdon's site. Min is 97 and max is 101 gr, a compressed load. You could start at 98 or 99 and work up. I have a feeling that it might be too slow for that combination and you will run out of room before you equal Retumbo. It depends on your OAL. It usually works best for the heaviest for caliber bullets.
Kirby did some testing with RL-33 and says seating the bullet into the rifling it helps to lower ES.