- "Available by default, the silenced MK.23 pistol is averagely balanced, but still gets the job done."
- ― in-game description[src]
A predecessor the Heckler and Koch USP semi-automatic pistol, the MK.23 were designed by German weapons manufacturer Heckler and Koch. Developed as part of US SOCOM's Offensive Handgun Weapon System, the MK.23 was built to be extremely rugged, durable, and accurate as well as have features for suppressed use (such as a slide lock and threaded barrel). While the pistol's large size and hefty weight help to mitigate recoil and retain accuracy, it was criticized for being unwieldy and difficult to use in close quarters.
In Tom Clancy's Splinter Cell: Conviction, the MK.23 is available for use by the player. It is the first pistol available to Sam at the beginning of the game. It holds 12 rounds by default, 18 after purchasing the Extended Mag upgrade. It is a powerful pistol; after the upgrade, damage per shot is second only to the Desert Eagle, which suffers from the inability to accept a suppressor, making the MK.23 more practical for stealth situations. The pistol's main drawback is that only two enemies can be executed with it at the same time. It is the only pistol that cannot mark more than two targets. It also has poor accuracy at mid to long range (unlike the real-life pistol, which is considered a match-grade weapon), or firing rapidly, but the laser sight upgrade will help with that issue a bit. The MK.23 is Sam's default weapon for early levels of the game, before being replaced by Five-seveN in the Washington Monument mission. Because the player has infinite rounds for sidearms in this game, the MK.23 should serve the player well in early stages.
|Extended Mag||300 points|
|Laser Sight||250 points|
|Hollow point ammo||250 points|
- Outside of the Splinter Cell games, the MK.23 is also known as the "MK.23 SOCOM"; it is one of the most notable sidearms used by the character Solid Snake from the Metal Gear Solid franchise, another known Stealth franchise much like Splinter Cell.
- The MK.23 also makes its appearance in the original Splinter Cell and Chaos Theory as enemy weapons, with the silencer removed.
- The MK.23 seems to be the standard sidearm for the Splinter Cells in Splinter Cell: Conviction, replacing the Five-seveN.
- The MK.23 can use special ammunition, e.g. the tranquilizer dart used by a Splinter Cell to knock Sam out.