Quote Originally Posted by C-grunt View Post
I remember reading when this first started that the Army chose .277 because they found it was the "perfect" caliber for a combat rifle after their testing. Why is it better than a 6.5 or 7mm bullet? Who knows.
From what I understand, 6.5 has the flattest trajectory and highest BC, 7mm has the best terminal ballistics and barrier penetration, and 6.8 is a happy medium between the two. They found the same thing when they were developing the 6.8 SPC, and even back before that, when they developed the .276 Pedersen.