With my AIMC .338 LM I have played with the 285 ELD, 300 SMK and 300 Berger with the H1000, Retumbo and N570.
I have found the 285 ELD and the N570 at 2900 FPS (work up to this) is my best LR choice. I shot a 2.18" 5 shot group with a 6-8 tail wind at 600y.
My SD was 4.8 fps.
Its a hammer out...