I clicked on this thread out of curiosity, because I'm tossing around the idea of using my .260 Rem for elk sometime (I'm also conservatively pushing a 139grain bullet above 2,700 fps, and could probably easily get to 2,850fps. And I can absolutely put my bullet where I want it out of the rifle I have chambered in .260 Rem).
To me, I just don't see a 120gr projectile at 2,500 fps being sufficient for a heavy-boned animal like an elk. In a survival situation? Yeah, absolutely. In a normal hunting situation? It just doesn't seem like it has the juice to reliably produce a clean kill.
I know we live in the days of "magnum envy", and every hunter at the gun counter wants to have the next biggest, baddest, Super-Dooper-Ultra-Deathray-Magnum on opening day. But, I've never subscribed to that philosophy, so I'm not speaking from that bias point as an individual. Like many others, I've gone the opposite direction with my thinking on that subject, favoring shot placement above ballistics (to an extent). Personally, I think a .308Win is plenty for elk, and I'm considering my .260 Rem as an option. I've also known plenty of hunters who were successful with both of those calibers.
Still, there's got to be a place to draw the line on the low end of the spectrum, and I just don't see 120gr @2,500fps as being a really wise choice. Maybe I'm wrong? That's likely a philosophical question, since someone is always ready to point out the fact that "a properly placed .22lr shot can kill anything that walks on this planet". Yawn. Your milage may vary!