"Scott Ferrin" wrote

Some
improvement in range is possible. Much higher is questionable.
ASRAAM
and Python have much larger motors for the same generation seeker
technology (same seeker in ASRAAMs case) indicating that designers
not
tied to a large stock of existing ordnance feel that more impulse
can
be usefully employed exploiting the seeker's performance.

IIRC all the rest of the entries for which the -9x as-is was
selected
had bigger motors too.

Yep, they did. The USAF perhaps feels less need for a long range IR
missile since AIM-120 fills that range bin.