Just shooting at paper at longer ranges, I will take my .54 over my .50 for longer shots, but that's paper and not game. I trust myself with my .50 to 100 or just over, and my .54 to 125 or just over, but that is under perfect conditions. Now I used to shoot my .50 to 200 and 300 yds regularly when I had access to a range that allowed those ranges, but am limited to 200yds now, and the drop on either caliber with my loads is enough that I will not take a 150yd shot with either on game. Most of the time, when I try, I can get inside 50yds, and often inside 20, so I dont have a need for the long shots in my area. Back when I shot instead of hunted, I would take much longer shots with modern stuff, and I still can take those shots with a modern, but to me it comes down to this... Do I want to shop with a modern, or hunt with a ML? Because with the heavy .308 I used to "hunt" with, if I could see it, I could take it, and with that kind of performance, I may as well go buy a steak becasue that is about as challenging as it was. I knew how to hunt, but used that .308 for everything back then. The last deer I took with it, I snuck up to a deer and took him at 12 yards with a 26" heavy barreled .308 bolt action with a 10X scope on it. Did I mention this was at 12 yards? I think it is almost always possible to get to around 100yds, and actually hunt. Now I know there are exceptions, and there's a few members here who have said repeatedly that long shots are the rule where they hunt, but even they usually seem to report 150yd shots, IIRC.
Having said that, I do completely agree with practicing at longer ranges as it will make the 100yd shots seem like childs play when you have fur in your sights, but please dont take long shots on game as any slight mistake in range estimation on your part can make the difference between a clean kill and a long lingering very painful death.