Sorry I'm late to the party...I've just gotten done with reading through 21 pages of posts to see if anyone invoked Warren Page's article...no one did directly. Shame on you MuleDeer!
Warren Page gained access to the Remington Custom Shop's test firing records for their ultra accurate 40-X's in it's various chamberings. This is for hundreds of rifles test fired under ideal conditions (same very experienced shooter, benched in a tunnel). Keep in mind that Remington had a reputation to uphold because they provided a 1/2" guarantee for certain calibers. Also keep in mind that Mike Walker was a serious benchrest competitor. Page's article provides a graph of average group size for each cartridge. The graph starts on the left with the 222 Rem averaging .363" and as the caliber increase, so does the group size...except the 308 Win which is an anomaly in the trend at just over a half inch. The 30-06 is the next largest cartridge and it shows a significant jump in group size at 0.768"
Since others have mentioned the 30-06 for Highpower Rifle Competition, I'll offer that one of the longest standing records in the sport, the 1000pt aggregate was set by in 1968 by Eric England of the USMC shooting a 30-06 Win-M70 bolt gun; 998-45X. This record stood for over 4 decades through the rise of the 308. It took Sheri Gallagher of the USAMU shooting a TUBB-2000 in 260 Rem to beat it.
Other's have mentioned German Salazar's work comparing the 308 and the 30-06 prone on the 600 yard NRA Highpower target. Other's have dismissed it as "meh" or BTDT. That speaks to "you don't know German". He had identical rifles built with different chamberings, and loaded them both to his extremely high standard. He then tested and competed with both over the course of many matches, rounds and months. At the end of the day, the two cartridges ended in a statistical dead heat.
The NRA Highpower Target lacks resolution to separate accuracy between the two cartridges. These two examples are a testament to the skill of the shooters. But the 30-06 can certainly deliver on the NRA Highpower Target.
