just by chance was it the orange box bergers?
Last year I used the yellow box "match" bullets with decent results, they did exit a doe at 419 yards, then this year I switched to the orange box also in 140 gr .264 loaded in my 6.5 Gibbs at 3160 fps. I shot 2 bucks, (457 and 493 yds) about where you hit yours, both traveled in excess of 3/4 of a mile, just a trickle of a bloodtrail, both had simular entrance wounds to yours, and no exit, I'm goin back to the yellow box.
RR