RL-33 is different than many powders. It has a longer burning curve like RL-17. Perhaps that is where some of the extra heat is coming from.
From my documents file:
RL-33 is only the second of a line of unique powders offered by Alliant. Borrowed this line from an ad: "New Reloder 33 Delivers More Speed in Big Magnums Now Alliant is introducing a new powder, Reloder 33, that uses the same kernel-impregnation technology first pioneered in Reloder 17. Alliant Reloder 33 is a new powder created by Rheinmetall Nitrochemie.
Be careful trying a bunch of powders and bullets. It won't be long before the barrel is shot out. I know I did it to a 257 weatherby. Learned plenty and the second barrel only shoots one bullet and one powder. Incidentally the powder is RL-33.
