.25-06
Gidday mate.
As for hunting; I've used both the .25-06 and the 257 Roberts on game (mostly in the South-Isl of NZ) in the past and have also tried most other cal's. over the yrs. However, I've taken most game very effectively with the 6.5 bore-sizes: reason this is still my favorite cal.. Aspecially the new 6.5X47 Lapua is not only an awesome performer in a neat, small & very efficient case for target-range practise, but it has already proven itself very succesfully on game during this years hunting-season!
*The .25 cal might be a great performer on game and be able to shoot out to ranges of 600mtr plus; however so do most other calibers with some practise! When it comes to Longrange target-shooting: projectiles in the .25 cal. bore size are lacking several things the 6mm, 6.5mm & 7mm's ( plus .30 & .338 cal. to a slightly lesser degree) do have!
*Most importantly: It all starts with a great selection of Match bullets. Check your BC's & SD's on your .25 cal. bullets and compare them to that of the 6.5 & 7mm bullets? You'll notice that there is quite a difference in the nr's; reason manufacturers won't produce them for your favorite cal. mate.
I guess the .25 cal. would need Match-bullet weights of around 130-135gr. to get near the 6.5's /140-144gr figures and this would be an awfull long pill: comparable to the 6.5 /155-160gr. props!
Who knows: maybe in time they will put out some heavyweight .25 cal. Match-projectiles?
Cheers,
Jan