This one belongs in the category of 'MYTHS' as in members repeating what they heard on the Internet and have repeated it so many times they believe it.
MBRO, thanks for showing up, it has been lonely over here, I had the opportunity to acquire all or any part of 100,000 + cases in the category of popular loaded cases that were test fired with different types of gages from a member of another forum, to me they had no value EXCEPT for reloading.
I have weighed cases, sorted cases and measured cases, because of what seems monotonous I made a height gage sorter to speed things up, as to difference, the military case can weigh the same as a commercial case and be different, not an easy sale but the case head on military military cases is thinner than the case head thickness on aa R-P commercial case head by .060 thousands, meaning the case head thickness on the military 30/06 is .200 (+ or_), The R-P case head thickness is .260, deductive reasoning says if the case head is thinner but weight more the case body is thinner, That leaves the military case with a thin case head and a thick case body. that may not seem like much but it does effect the powder column. The military case will have a long powder column that is small in diameter. The commercial case with the thick case head will have a short columns of powder that is large in diameter when compared to the military case, then it is to be decided if that makes a difference, mu opinion 'yes'.
The 308 W is a short case when compared to the 30/06, the powder column of the 308 is shorter with a larger diameter than the 30/06, the 30/06 powder column is longer in length but smaller than the column, of powder in the 308 W, conclusion/ Deductive reasoning? the 308 keeps up with the 30/06 when using 150 grain bullets, so the advantage goes to the short column with the large diameter.
F. Guffey