I run some 400's at about 1,750 fps with 55 grains of H4895. Haven't decked anything with it, but it definitely gets my attention when I light one off. No desire to push them any faster.
IIRC - With the Speer 400s I stopped at 45 gr of IMR4198. Think it was supposed to be ~1,900 fps.
I know it gave me eyeball floaters...
Accurate as all get out, but you wanted to not forget your lead sled at the range...
That being said, I have Win factory 300 HPs packed for deer cap this year.