I dont know about LO etc, but harbah likely ditched the expensive tercom/dsmac setup which isnt really needed for anti shippers because theres no ter to com lol.Why not give this capability to babur as well? I get that this is more needed for AShM roles but f4 being harbah based doesnt really make sense to me, yes its LO but isnt it also 150kg lighter. With less weight restrictions on land based launchers f4 could be something with far more range
thats likely where the weight difference comes from.
the issue with just throwing more fuel at it is the fuel also weighs an amount, thus, imposing a penalty on the missile due to it being heavier, so at some point your returns start diminishing, the solution to the range issue is a complicated one because it relies on better engine tech, not fuel


