Quote Originally Posted by pinzgauer View Post
If you look at the deaired max recoil and ammo weight profile combined with the performance expectations down range it's pretty clear that a 6.5 projectile will be a sweet spot for carbines.

Especially when vest penetration (requiring velocity) , BC, sectional density is factored in.

I expect we'll see 90-115g projectiles, lead free, etc. 6.5mm is the sweet spot for those.

This also applies to comments in the other thread on creedmore about adoption of 6.8 spc. My prediction: ain't gonna happen. (Or Grendel, or any other non-caseless breakthrough)

Just too many compromises (capacity, weight) with the offsetting improvements1 not solving perceived critical problems at hand. (Talking about big army priorities, I know all the advantages Grendel/spc offers. I'm sold. They are not, yet.)
Sorry but SD doesn't mean jack unless the projectile is a solid and never changes shape. As soon as the bullet contacts something and the bullet changes shape that SD figure means nothing. Any caliber bullet can be made with the same BC using a /cal formula. The weight difference between a 6mm, 6.5 and 6.8 bullet with the same BC is only about 6-8gr. With a case the capacity of the Grendel or 6.8(36gr) the 6mm will have better exterior ballistics for long range but the 6.8 or 7mm will have better terminal performance considering bullets of identical construction.