Rl22 and 140 ttsx. Have not used it on elk but would not hesitate to after using it on several deer
The 140 ttsx is a nasty one at speed. Killed a deer at about 40 yards or so and the bullet went full-length through. Instant drop, but that was via one of my 7 WSM's. I can't imagine there would be any difference with a 280 AI.