My chronograph has never shown these results. A friend of mine spent a whole summer with his .308 and his .30-06 pushing 150 and 165 grain bullets with every available powder. He used his two .308rifles ( a Remington and a Winchester) his Remington .30-06 and my Winchester .30-06 and filled up a log book with his results. He started with 200 new pieces of brass (Remington and Winchester) for each rifle and discarded them after 5 loadings each - at which time he put new brass from different lots into use. Using my chronograph he always noted higher velocities from the .30-06 rifles and better accuracy with the highest velocity loads from both .30-06s. The .308s were very accurate rifles but only really showed it with their mid velocity loads. Overall he found tighter groups with his .308s than with the .30-06s (but not by a significant amount) and higher velocities - and most importantly higher usable velocities - with the .30-06s.