Assuming your long actions are '06 bolt face, I'd go 6.5-06, or if you hate case trimming enough, the Ackley version of the same. One pass through the 6.5-06 die with a .270 case and you're done. 8" twist, of course…
John
+1. I was going to say .260 Rem until you included 1,000 yards and the long action. You'll get an extra 100 fps with the AI if you want it.
