I'm going straight 280.
Lapooey brass('06),drive a false shoulder for positive initial headspace,size in accordance for Round Two,trim the Lot square and never trim again. 700 Donor,Bart 8.7" MTU at 23",HEAVY solid filled A5,S/S Matt BDL bottom,Marty 45MOA extended 1913 and Bushy 3-12x LRTSi.
It will eat only 180's and stay Supersonic to 1700yds+ in all weathers.........................