One of my hunting friends has a strategy that I think is applicable to this question.
My buddy like to try to match or complement the weapon to the prey or the style of hunting he wishes to pursue.
For example he would choose a muzzle-loader or Sharps if he were to go on a Bison hunt. This makes the hunt more interesting.
The same principles can be used when long-range hunting. We use scoped target .22 rimfires for hunting gophers out to 200 yards. This is a long shot for a .22 but as mentioned previously it is nothing special when I am using my 6BR.
In that case the 6BR is used for longer shots on gophers or coyotes.
Once we really begin to step out byond 500 yards, the big .30 cals come out. These can be used on gophers, coyotes and deer.
For really long shots, the next step is a .338.
So what you see here is not a strict definition of what is long or not but what is long for the rifle, equipment AND the target.
When I first expressed a desire to hunt deer long-range, a friend suggested I start with a 100 yard deer to get a feel for the hunt. To me this was a completely ludicrous idea because I was used to shooting very small targets like gophers at ranges out to 500 yards and I shot competition out to 1000 yards.
To this guy, with his equipment and shooting experience, 100 yards was a decent range. To me, with my equipment and experience, it wasn't any sort of challenge at all.
I think ultimately we do this type of shooting for the challenge, to make ourselves better marksmen. The degree of difficulty (to borrow a phrase from figure skating) always encompases three factors: Equipment, Target and Range.
Peter Cronhelm