The Crosman NightStalker is the first semi-automatic

Semi-automatic rifle

A semi-automatic rifle is a type of rifle that fires a single bullet each time the trigger is pulled, automatically ejects the spent cartridge, chambers a fresh cartridge from its magazine, and is immediately ready to fire another shot...

 airgun featuring blowback action

Blowback (arms)

Blowback is a system of operation for self-loading firearms that obtains energy from the motion of the cartridge case as it is pushed to the rear by expanding gases created by the ignition of the propellant charge....

. Released in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 in 2005, the NightStalker uses an 88 gram CO₂ powerlet as its power source.

It fires .177 calibre (4.5mm) pellets from a 12 shot rotary clip at up to 580 ft/s (176.8 m/s). It is a carbine of modern design, weighing 3.27 lb (1.5 kg). Its total length is just over thirty inches (76 cm); its rifled barrel is 16.75 inches (42.5 cm) long.

The front and rear sights use Crosman's Mohawk sight system which allows the user to alternate between two different diameters of windage adjustable peep sight while incorporating a front sight that is adjustable for elevation. A safety mechanism is provided by a cross bolt safety switch.