Hey Bugger, I am shooting the .510, 400 grain CEB lever gun solid and the 450 grain Swift A Frame in the 50-110. Velocities are in the 2000+ FPS range, the heavier A Frames actually shoot a little faster. I have taken a buffalo with each bullet.
The 45-90 is shooting the .458, 400 grain CEB solid at speeds up to 2100 FPS. That is one loooonng bullet and it takes up a lot of case capacity.
