Here is what I was able to get with my 280.

Kimber Montana, 160 Nosler AB, Fed 210 sparks

Re 26

59 grains averaged 2794, 0.95" gross
60 grains avg 2863, 0.66" gross
61 grains avg 2968, 1.02" gross

Ramshot Magnum

63 grains averaged 2757, 1.39"
64 grains avg 2809, 1.13"
65 grains avg 2855, 1.44"

Adversity doesn't build character, it reveals it.