A difference of 100 fps or 200 fps might (maybe, maybe not) make a significant difference between two cartridges if they were shooting .204/.223/.243/.257 diameter bullets at less than 75 gr. at targets more than 500 yards away. Maybe... Possibly...

I am extraordinarily confident that 100-200 fps difference between two cartridges shooting 400-gr solids at big, dangerous animals at less than 50 yards will never be distinguishable by anyone -- strictly on velocity differences.

That being said, I have a .404 Jeffery and shoot 400 gr solids at 2300 fps. I have utter belief that there is no functional difference between it and a .416 Rigby shooting a 400-gr soild at 2400 fps.

FWIW...

Dennis

"The more you run over a dead cat, the flatter it gets."

"If you're asking me something technical, you may be looking for My Other Brother Darrell."

"It ain't foot-pounds that kills stuff -- it's broken body parts."