The Tactical Knife Flip or 'Tact Flip' is a trickshot that can be done in Call of Duty: Modern Warfare 2. It involves the players' tactical knife flip in the 360 degree vertical motion.
The trickshot can be achieved by double tapping triangle (PS3) or Y (XBOX) and sprinting when the primary weapon is switching to the pistol.
The Tactical Knife Flip can only be done with the USP.45 and the M9 pistols. It cannot be done with the Desert Eagle or .44 Magnum.