I believe it boils down to shot placement and proper bullet performance (expansion vs. penetration) as well as being comfortable with your rifle. If you can't make a good shot then you should let the deer walk.
If you put the proper bullet in the right place then the .308W will kill any game animal in North America within 300y. You don't need Swift A-Frames for thin skinned deer and Core Lokts are probably not the best choice for bear.
For that matter, I hunt whitetails with a .300 Savage (150gr Rem CL) sporting a 20 inch barrel. It has a slower velocity and less energy than a .308W but drops the deer on the first shot.