The HK MARK23 is a weapon featured in Tom Clancy's Rainbow Six. Functioning similar to its counterpart of the original game, the suppressed variant, known as the HK MARK23-SD is also featured in the game.
The extreme ruggedness, reliability and match-grade accuracy of the .45 Caliber Mark ACP has made it handgun of choice for western Special Forces. A specially designed sound and flash suppressor virtually eliminates muzzle flash and provides more than 35dB of sound reduction. It is an essential part of any RAINBOW mission requiring both firepower and discretion.
Tom Clancy's Rainbow Six and Rainbow Six: Rogue Spear
The Mk.23 in-game is incorrectly modeled exactly the same as the HK .40 USP.
In Tom Clancy's Rainbow Six: Rogue Spear, the "Black Thorn" expansion pack changed the name of the weapon to the ".45cal M23"
Tom Clancy's Rainbow Six Vegas 1 and 2
In-game, the MK23 has the front cocking serrations of the Phase II prototype of the weapon. It might be interesting to note that these front cocking serrations were deleted from production models of the weapon.