Technically speaking, near-absolute knockdown effect can be achieved with about any caliber cartridge by what we can call the "lights-out" method, which is either a brain shot or a shot that shatters the neck vertebrae and spinal cord. The old-time deer hunters I grew up with were great believers in the neck shot because it minimized meat loss and, more important, usually dropped the animal in its tracks. Those were the days when calibers such as the .30/30 and .35 Remington ruled the woods, still-hunting was practiced by almost everyone, 50 yards was a long shot and open sights were the norm. Today, with much-changed hunting techniques and equipment, we don't hear nearly as much about hunters favoring neck or brain shots. This is just as well, because aiming at the smaller parts of an animal's anatomy is, literally, a hit-or-miss proposition.