The farthest shot with a 6x284 that I had ever heard of was 1115 yards..."the bull was just grazing out in the open, so he wasn't on the move. He shot it twice. First shot was a double lung and it coughed blood on the hillside around it, took three steps and turned 180 degrees then he shot it in the shoulder and dropped it."
This info was from best of the west. I believe the load was 105vld @ 3340fps.
A 243 winchester with 22" barrel can send the 105vld @ 3050fps. So the 243 produces 1998fps/931ft-lb @ 900 yards. The 6x284 produces 2018fps/949ft-lb @ 1100 yards. (The actual numbers are probably higher due to higher velocity creating higher bc than stated from bergers)
Trust me folks, I recommend my family member to NOT USE a 243 for elk hunting. They all should use 300 win mags.

So they can buy cheap bullets from walmart and still do fine for elk hunting. I'm addicted to long range shooting and shoot hand loads only so its different for my situation.