I decided to do a bit of math and found the old 257 can still whoop the Fadmoor!
I determined for each the odds of killing a deer at 300 yards with the following parameters:
And the result?
Creedmoor was snatched. Doing pretty good for a 70-year-old cartridge.
(the results may change if you own a laser rangefinder and are allowed to use it in season)