Thats great that PAF and IAF have almost smae range of bvr missile. but i have read on wikipedia about the brahmos supersonic cruise misslie that has range of 300 km installed on Su-30mki termed as AWACS killer
The K-100 "AWACS killer" is the weapon I believe you are referring to.
Plain and simple it is a myth. It has been in development "for ever" and has not ever been deployed by anyone.
The reason is simple.
Even with ramjet propulsion, the weapon has to glide for a significant proportion of it's flight. In order to achieve such a long range it needs a very clean missile body, ie: no fins, which means the missile is very non-maneuverable.
It also needs to fly at VERY high altitudes, some say up to 100,000 feet to achieve it's range performance.
Furthermore, it needs it's own very powerful active radar system to be operational at all, which means that EVERYONE will know that this thing is coming.
So what this weapon provides is a very high speed missile, that is "gliding" for the majority of it's flight profile, at an extremely high altitude with a VERY visible active radar emission and very large thermal bloom from it's very powerful rocket motor operating at high altitude, before descending in a "top attack" profile.
In short, every aircraft in a theatre WILL know when this thing has been launched, everyone WILL know it's performance, it WILL be the focus of jamming and due to it's lack of maneuverability and extended flight time (despite it's speed) every aircraft, including large jets like AWACS, AAR etc, should be able to out-maneuver the thing.
The Americans had a similar weapon 35 years ago. It was called the AIM-54 Phoenix. It's limitations were realised and it was intended to fly towards and attack massed bomber formations, in the manner described above.
It's performance against an individual platform was very ordinary, which is why the US has not deployed any similar weapons since the threat of attack by mass bomber fleets disappeared...
The USA has many missiles that would perform a similar role, including Patriot PAC-3 and ESSM, but the effort isn't worth the result. The Air Power Australia argument that K-100 type missiles render "small" fighters impotent and spell the end of Western Airborne ISR superiority is utter nonsense.
Even if current weapons are insufficient, a PAC-3 Patriot or ESSM missile adapted for fighter carriage would provide a standoff range capability that matches or exceeds the K-100 itself and with hardpoints designed for 2000lbs weapons carriage, lofting these sorts of missiles would present no problem.
That they see no need for carriage of such long ranged weapons, shows this "threat" as it really is...
Hence why not even Russia employs this type of weapon, despite having developed it for the last 20 odd years...