Machine Pistol

The  is a class of secondary weapons introduced in Call of Duty: Modern Warfare 2, as well having been featured in every game afterwards. Machine Pistols are generally a hybrid of a Pistol and a Submachine Gun, having the size, damage and range of a pistol, but featuring the fire rate (and sometimes even magazine capacities) of a Submachine Gun. They are used under their name in Modern Warfare 2, Modern Warfare 3 and Online, but are classed with other handguns in Black Ops, Black Ops II, Black Ops: Declassified, Ghosts, Advanced Warfare and Black Ops III.

Call of Duty: Black Ops
When equipped with the Full-Auto Upgrade, this weapon functions like a machine pistol, yet it is simply classified as a handgun. 

Call of Duty: Black Ops II
The weapons mentioned below function like machine pistols, yet they are simply classified as handguns in-game. 

Call of Duty: Black Ops: Declassified
Likewise, these weapons are classified as handguns in-game. 

Call of Duty: Ghosts
Like in Black Ops II, these weapons are simply classified as handguns in-game. 

Call of Duty: Advanced Warfare
Similarly, these are classified as pistols. 

Call of Duty: Black Ops III
These are also classified as pistols.
 * L-CAR 9
 * Spyder
 * Triton