With your objective 154s @ 2500 you shouldn't have any trouble at all. The only negative about BlC2 and other ball powders is 'temp sensitivity'. I've used it and H 335 w/o major differences in our temperature brackets.
IF, IF you load/chrono in hot wx then I think you'd expect to see vel drop in 'COLD' wx. As MD points out the biggest problem with that is change in POI which would affect scope sighting.
Otherwise load, shoot and enjoy.
Jerry
