I don't think expansion should be a problem on PD and squirrels at 1000 yds
Seriously though, I shoot the 115 DTAC moly out of my 243 AI @ 3178fps. It is very acccurate and I have taken a PD at 734yds. Third shot to dial it in, but 4 mph wind enough to push it around at that distance.
I am very happy with it. 585 BC gives it great accuracy.
I'll send ya few if you want to try em out....