I have no experience with the 125 grain. But I'd guess it will shoot flat. Bet it will be a good varmint round. My Sierra book says the following:
These Loads can kill you and blow you up. ect.
748 powder 125 grain
Start 33.5 @ 2200 fps
34..9 @2300 fps
36.3 @ 2400 fps
Max 37.6 @ 2500 fps
I must say each time I have compared my chrono data to Sierra's charts they seem very optimistic. Since 748 is a bit temp sensitive, I'd keep em on the slow end, as summer is coming. Not knocking 748, I think it is best for 30-30.