The most powerful handgun cartridge on the market right now. Yes it beats the Desert Eagle's .50AE and Raging Bull's .454 Casull. This monster is 12.7 X 41mm (read: it's huge). In comparison, the cartridge you stick in AK-47s is 7.62 X 39mm and M16s use 5.56 X 45mm (interesting to note that .500 actually produces more muzzle energy than 5.56 NATO; however, because the barrel is shorter the energy drops off faster)... The gun you stick this bad boy in weighs close to 5 pounds loaded and is a complete beast. Basically, you shoot something with this, it dies.
I brought down an African Elephant in 1 shot with my shiny new .500 Smith and Wesson.