Bottom line... know the capabilities and limitations of your rifle, load and yourself.
-MR
+1 to that. That's what responsible hunters do. Hunting isn't the time to get macho and show off to your buddy that you can hit that elk that's "probably 700 out there". Save that for practice or rock busting. Hunting is about KNOWING you can make the shot. You've practiced the shot and you know your equipment can make the shot. Doesn't matter if its 10 yards or 1000, if you don't feel confident don't take it. Hunting big game isn't the time to try a shot for the first time. A lot of guys can hit WAY out there but only do so in practice. (I'm probably quoting this wrong but in one of his articles Shawn Carlock talks about checking drop using some 1500 yd+ shots, not because he intended to shoot that far but because if you're drops are on at 1500 they will be on at 700. He also talked about how practicing at extreme range makes long range look short!)
If you know you can put a bullet in the boiler room at that range and the bullet will perform at that range then go for it. If there's any doubt don't. I've taken elk at 400 yards with my .270 win but it was a shot I had practiced and the shot was a perfect broadside. Wouldn't have taken it if the elk was another 50 yards out because 400 is where my loads for that setup start to drop off the table and I wouldn't feel confident in a hit.