without a doubt in my mind it would have to be a 6.5x.284 Norma , everyone knows that 6.5 m/m is the perfect bullet dia.even if you won't admit it . The 6.5x.284 has every thing you want ,excellent 1000 yd.accuracy fron a 140 gr. bullet with a ballistic co. of 600 +/- that hits on target like a runaway locomotive. Whats not to like ?
I'll go with the .338 Lapua/.338 Edge. this thing is such a good long long distance calibre the game dont even spook as you knock em over 1 x 1 although i still have very soft spot for my 7mmSTW on my Ruger No.1 action with which i have taken chamois and Thar from across some mighty big valleys.(but it's not on the list)