I know I've shot enough groups at 300 and 600 with my 223 and a 6.5 twist and 90 jlks, to know that I'm hard pressed to get a 3 inch group at 300 ever, usually over that.... and I'm hard pressed to ever shoot a group over 3 inches at 600...
I know thats not a shrinking group.... but it sure says some strange things that are repeatable.
I have shot enough groups that also do show smaller MOA the further out, but not repeatable enough to be reliable in my mind.
Jeff