Twice? Four or five times, I'd say. Heck the ball is more'n three times as heavy as a standard 5.56. And a gigantic load of powder pushing it.
The Garand was overpowered, and the U.S. seriously debated going to a .308 (7.62x51). Reason they stuck with the .30.06 (7.62x63) is that the entire ammo industry was already tooled for it.
There was actually a thread of opinion in the U.S. military when I was in that the 5.56x45 was chosen because, in terms of combat effectiveness, it's actually better to f*ck up an enemy soldier than to kill him, because you tie up enemy resources in taking care of him.