26" heavy contour barrel (#6 sporter) on M70 classic.
Hedging the lengths so as to be useful for special purpose and general purpose loads.
And nowadays the 3.340" COL and 60,000 psi SAAMI .458 WinMag makes a bloody big hole through anything needing a bloody big hole, in the most practical manner.
I have no idea what the actual contours of the M70 Super Express at 22" and the Mark X / Whitworth at the near 24" equate to, but I like them both for a general purpose rifle. The Mark X / Whitworth may eventually receive a trim to 22 or 21".
I think the barrel contours for the Winchester 375 H&H Safari Express and stainless classics also are more appropriate to 458's. Though not too shabby in .416.
Edit = I fully agree on the 1-10". No idea how that would do with hard-cast powder coated bullets ??