As per your comments our military is producing and utilizing G3 for 60 years. So why we shouldn't wait for another decade to closely observe the pattern which the global powers are shifting towards and after that decide upon the future standard issued rifle for our military.
The battle between the bullet and body armor has got fierce in recent years. There is already an experimental lightweight soft body armor prototype in the market which is capable of stopping 50 bmg round. That's antimaterial. 50 cal round which cannot penetrate through a soft body armor light enough to be worn by a man! Can you imagine this technological leap! Yeah I know the impact and blunt force, kinetic energy of the round is enough to convert the internals of the body into jelly and incapacitating the soldier.
So I fear by the time we accomplish the task of equipping our soldiers with whatever rifle from the list, it would already be an obsolete rifle and an obsolete round by then and a poor country having weak economy can't afford to keep changing the millions of service rifles for its armed forces at an interval of 10 to 12 years. Bulk of our air force still use 60,70 years old designed F7s and mirages, Soviet Era tanks, and similar condition with the navy too.
Yes G3 still fires a bullet, 7.62x51 still packs a punch, capable enough to injure and kill modern enemy soldiers, terrorists but this round is certainly not future proof that's for sure.
We don't have a penny to spend on R&D so why not simply follow the tracks of our beloved America, or55 Russia, Europe and China. They have big $$$ to throw into R&D and they are the ones who shape the future of the combat and according to them the life span of existing 5.56 and 7.62 ammo is going to expire soon.
But by then the bullet fired from an old rusty G3 and a brand new expensive desert tanned beauty of SCAR-H would have the similar impact upon whoever is on the receiving end.
The real question is would the rifles under consideration and rounds they are chambered in as of now, be relevant and as effective after 20-30 years from now or not?
That was the real theme of my previous comment too which you cleverly finesse through.