These are the velocities out of my personal 340 wby custom with a 28" Douglass premium barrel that I have shot since 1977. It has taken elk at amazing distances with the 250 sierra gameking. At the time it was the highest BC bullet available in any caliber.
With the 225 nosler AB the accuracy load is 3212 fps with a deviation of 4 fps in a five shot string. I have shot it up to 3260 fps.
My long standing accuracy load with the 250 sierra gameking that has taken numerous animals at long range is 3056 fps with a standard deviation of 2 fps. I have shot it up to 3100 fps.