Dan,

there is more to the world than the US of A.

obsolete means - "out of use"

The 7x57 never was "in use" in the US. So it can not be called obsolete, especially when, in the countries, where it has been used from the beginning, it is going strong. No end in sight.

As for the system length question -

COAL .30-06 3.340"
COAL 7 x 57 3.074"

Difference .266". I rest my case.

Just my two cents.

All the best.

Member of the Merry Band of turdlike People.