Unlock the Mk. 23 handgun, also known as SOCOM from Metal Gear Solid in Metal Gear Solid 4: Guns of the Patriots for the Playstation 3.
1. Access the Password Menu under Extras. This is only available after you beat the game once on any difficulty setting.
2. Enter mekakorkkk as the password.
The Mk. 23 will be available when you load a saved game, or in a new game when you meet up with Metal Gear Mk. II.