You can get more powder in the Express case than the .280 case.
So it's got to be faster. The 7-06 that Dober brought up will hold more than the Express.
So maybe it's the best?
Close. I beleive the story was that SAAMI specs allowed the Express to run at higher pressures--to high for Remington's autoloaders. Remington reintroduced the Express as the 280 with lower SAAMI pressures offered in their auto loading rifles.
GB
