Which component is NOT part of handgun nomenclature?

The fire selector is not considered a component of handgun nomenclature. Handguns are primarily designed for semi-automatic or revolver operation, which typically do not include a fire selector feature. A fire selector is more commonly associated with military-style firearms, such as rifles, that can switch between different firing modes, like semi-automatic and fully automatic.

In contrast, the other components listed—trigger guard, muzzle, and magazine release—are all essential parts of a handgun. The trigger guard protects the trigger from accidental discharge, the muzzle refers to the front end of the barrel where the bullet exits, and the magazine release allows for the insertion and removal of the magazine that holds ammunition. Each of these parts plays a critical role in the function and operation of handguns, making them standard components in the nomenclature related to them.