Which one is better cartridges for log rang shooting ".308 or 30-06?
For plinking, or competion?
Basically 308 win is better.
If you go to comoetition under ICFRA f class rules then you have two disciplines, f open i ftr.
Discipline ftr (target rifle) is only for caliber 223 rem and 308 win.
F open is for any caliber, up to 8 mm.
So, if you want ti shoot 30 06, in long range they will put you in class f open, where competition is strong with better calibers such as 6.5 cm, 6 and 6.5br, 6.5x47 lapua etc.
For competiton in other long range associations, like prs etc, in competition with other calibers oh high ballistic performace 3006 has not been proven.
F class with specific ftr rules gives monopol to 308 win.
But in reality bullets in cal 30, due to cip and saami standars, are too short and too fat, to be too much competitive. Lower bc. On the other hand, class 6 and 6.5 is much more ballistic efficient, long and sleak bullets.
Anyway, to answer shortly, 308 win is for long rang shooting (and hunting) 30 06 is for hunting.
To shoot at longer distances at target, give 308 win 30 inch long bull barrel, to get some extra velovcity and you can strech it quite long.