280 is awesome no doubt. You'd be very happy with a 280...much more so than either the 06 or 8x57 imho.
Id be hesitant however to try to fill any gap the exists between the 260 and 358. There is nothing a 280, 30-06 or 8x57 could do that your 260 couldn't do as well or better. Boring i know...but if it cant be done with a 140gr. 6.5 bullet...a .30 or .32 isnt the answer.
