RE: 338 Federal
Although I am a big 358 fan. There is one significant advatage of the 338 federal over the 358 besides the higher BC and SD of equal weight bullets in the 338 Federal and that is the much better selection of 338 bullets as compared to 358 bullets. This is particulary evident for light for caliber bullets.
On the other hand the 358 can shoot pistol bullets which is cool in its own way.