This is where the technological advances and experiences of tried and proven battle equipment from about the late 1950's onward comes out. Where the humble .303Brit was already forgotten for all intents and purposes, ongoing development of the .308/ 7.62 x 51 saw it making a name for itself as being a very adaptable case wrt propellant types and loads as well as projectile forms and masses.
I would not be surprised if the round is still in use in another fifty years.
I have had the pleasure of trying a lot of platforms for the 7.62 x 51 as well as the .338Lap and the 50BMG quite recently. I enjoy shooting the variety of arms and ammunition natures- nothing beats clanging a head sized steel spinner continuously at 800m, hitting torso sized out to 1500... but for real old style grin factor, I still roll out a No1 MkIII* and a few dozen rounds of MkVII ball (none of those squib rounds for me... the use of which will never show up a wandering zero in a No5 BTW...
) and shoot something that makes a noise when hit.
There are some things that money cannot buy... For everything else there is Mastercard