The 30 cal will shoot just as far, drift less and deliver more energy down range than the 25 cal. The very reason that most militaries in the world use the 30 cal as a long range sniper rifle.
Not saying the 250 isn't capable of taking game, just saying the 300 is better at it than the 250 is.
I shot an antelope last fall at 300 yards with my 300 in a 30+ mile an hour crosswind. Knowing that my 150 gr bullet dropped 10" at 300 yards I held 6" over the root of his tail and delivered the 30 cal ball behind the front shoulder.
I could have easily shot a box of 250 shells trying to hit that antelope under those conditions.
Just for fun I put a couple of typical combinations through Hornady's online ballistics calculator. I compared an .257" 87 grain flat base at 3000 fps vs. a .308" 150 grain flat base at 2600 fps, both of which are quite common combinations for the respective cartridges.
I set them as zeroed at 200 yards, and put in a 30 mph crosswind. Guess what? At 300 yards the 87 grain bullet drops 2.4" less, and has 1.1" less wind drift.
So your last statement may be a bit hyperbolic.
