Because modern all-copper bullets usually retain most, if-not-all, of their weight, you can start with a lighter bullet, which means you can start at a higher velocity, and the higher velocity makes them work even more betterer. That means a 120gn bullet can be plenty for elk, and a 120gn bullet will hammer any kind of deer or pig into the next county without a bunch of unnecessary recoil.
Its win win for those who choose to keep up with evolving bullet technology.
