bwinters,

I use 65.0 Magnum in my .280 AI with the 162 Hornady ELD-X. While 26 gets more velocity, Magnum proved significantly more accurate in this rifle, a 700 with a 22" Douglas barrel chambered by the late Mickey Coleman.
Muzzle velocity is 2815 with a CCI 250 primer, but would be around 2900 in a 24-25" barrel.

Haven't tried it with a 160 of any type yet.

“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck