The 338-284 has the SMALLEST capacity of the 4 cartridges mentioned.
Therefore with all other things being equal (they never are in reality) the 338-06AI would be fastest, then the RCM, then the 338-06, and finally the 338-284.

The AI has nearly 6 grains greater capacity than the 338-284.

The Chosin Few November to December 1950, Korea.
I'm not one of the Chosin Few but no more remarkable group of Americans ever existed.