I don't think I can ever hit an enemy fighter at 10nm with an AIM-120 regardless of altitude, speed or launch angles. So while our expectations may be off I still can't imagine what we have in DCS is even close to realistic.
Flogger from this it sounds like you are not certain whether or not you can hit an aircraft from 10nm out
I have only the Flaming Cliffs F 15 that carries the AIM 120 and I can hit an aircraft 10 - 15 nm most every time with a AIM 120, at 20 nm not so much, but I may not be using the equipment correctly. Yet
One of the difficulties I'm having is I do not get a valid shot cue until the aircraft is 15 nm out. So maybe user error?
Is that against a fighter though? A you sure you don't have it set to metric as well? I don't recall but I believe there is an option for the F-15.