LAST EDITED ON Oct-08-14 AT 02:59AM (MST)[p]Retumbo has been rather fickle for me in the 338LM.
I load most of my stuff with 300 grain OTM's, but do have some 250gr Scenar loads you could try if you work up to them.
I really like VVN560 for 250gr bullets, my load with the Scenar is 89gr, and gives over 3k.
H1000 is a more common powder and is pretty consistent for me, I use 92gr of it, again behind a Scenar.
I'm using Lapua brass and GM215M primers,drop down some and work up, as always,especially using different bullets.
The Scenar I'm using is very forgiving as far as seating depth, i dont know what rifle you're working with or what COAL it will allow, but if using these loads I gave, keep them off the lands, if you're jamming or kissing them, drop the charge accordingly.
a few powders to look for, if you havent already got some is
H1000
N560
N570
RL25
RL33
All those will get you where you want to be, and H4831 is also pretty decent if you cant find any of the above.
Sorry I have not worked with 300grain accubonds or 250 bergers, but H1000 works well for 300's too, and retumbo is actually a little better for 300's than it is with 250's.I know powder is scarce right now, let me know what you have available and I can tell you if i've worked with it before.