It's a fallacy that the original ball 150 grain load for the 30-06 had a muzzle velocity of 2700fps. The military didn't measure velocity at muzzle. They measured it at 78 feet. The velocity at 78 feet was spec'ed at 2700fps. The actual muzzle velocity was closer to 2780. The 300 Savage was never going to get to that number in a sporter-length barrel.
And that gets back to the question. What was the difference?
