With the "big bolt" that is now available, pressures for the Grendel round could safely be increased. But, along with increased pressure would come increased cost for licensing of the big bolt's production. However, if a military was interested in this concept, I'm sure they could pay for licensing it.
That still leaves the issue of designing a bullet. There was one Nato country that deliberately used a very brittle 7.62x51 bullet and jacket design that was made to tumble shortly after entry, and break in half at the cannelure. Then there were at least two bullet fragments making at least two wound channels. This could also be done with a 6.5mm bullet.
As long as the money was available for research, I don't see any reason why a bullet couldn't be made with two cannelure type indentations so it would break into three pieces each weighing around 40 grains.