CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.
I was surprised to see that the trend in the QuickLoad predictions was that the .308 was actually getting CLOSER to the .30-06 as the bullets got heavier so I went ahead and also ran the numbers for Hornady 220gr RN:
.308- Best noncompressed load, RL17, 44.9, 2,492fps, 108% compressed load, Ramshot Hunter 47.9gr, 2,498fps
.30-06- Best noncompressed load, Ramshot HUnter 56.9gr, 2,585fps, 108% compressed load, N560, 60.0gr, 2,654fps
Even here, where we've heard that the .30-06 "walks away" from the .308, we have only 150fps difference and only 93fps without going compressed. Any given difference between two guns/barrels/chambers could make up for that difference.
Still happily answering to the call-sign Peetza.
You do not HAVE a soul. You ARE a soul. You HAVE a body.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.