Pusher mechanism

A pusher mechanism, also known as a dart pusher, is an internal component of some Nerf blasters. It is used in almost all flywheel blasters.

Details
As one of its name suggests, it is a component that pushes a loaded dart (often enough from a loaded clip) through a flywheel system to fire it. The pusher itself is a rod of plastic that extends via firing trigger pull, manually with semi-automatic blasters and electronically with fully-automatic blasters.