I know the 142gr matchkings at 3000fps is a common load for 1000yd matches in the 6.5x284. I have NEVER heard of 3000fps with a 150gr 270 bullet. Most guys have problems getting there with 140s. 130gr 270 loads generally run 3100+ fps.
Personally, the one factor no one is mentioning is the higher SD values of the 6.5 mm bullets compared to the 7mm or .277 bullets. That is a bigger factor in game killing than BC values.
Try comparing the 6.5-284 and 270 in equal length barrels. Comparing 28 or 30 inch 6.5-284 match barrel velocities against a sporter 270 with a 22" barrel is obviously stacking the deck in the 6.5's direction.
