well, the reason why is because 1. it IS faster, 2. it is a much flatter shooting bullet. I shoot 135 gr. Sierra HPBT match long range (out to 863 yards is the farthest so far), and my buddy shooting a remington 700 BDL custom chambered in .308 has almost 9 inches more drift than i do. its all about the Ballistic Coefficient and load build up... powder, primer, casing, overall length/weight. when shooting that far, EVERYTHING makes a diff.
Remington 710 .270
Smith And Wesson M&P40
Mossberg 835 Ulti-Mag 12 Ga
CVA optima Mag .50 cal. Muzzleloader
1968 Browning recurve