FMJ yaw and upset performance

[stanc]

2. Exterior ballistics, in terms of a rate of velocity loss significantly less than 7.62mm M80 (probably around 0.50 BC).

With the bullet design settled it would then be easy to work back from the requirement to match the retained energy of the 7.62mm M80 at 1,000m...

We did some similar calculations on the old 65grendel forum. With the superior BC of a 123gr 6.5 Grendel load, it's easy to exceed 7.62 M80 energy @ 1000 meters. The trouble is that at the closer distances (<500 meters) where most infantry combat occurs, 6.5 Grendel doesn't come close to matching 7.62 M80 retained energy.