The Chimeran Sentry Gun is a fixed emplacement used by the Chimera to defend fortified and valued areas.
The Chimeran sentry gun is first seen in Resistance: Fall of Man. It fires what appears to be energized flechette at an alarming rate. It is absent in Resistance 2, but makes a reappearance in Resistance: Retribution.
A second variant of the sentry gun appears alongside the standard one in Resistance: Retribution. This variant fires an extremely strong flechette that usually can kill an enemy in one hit. This variant was eventually reversed-engineered into the Longbow railgun.
Resistance: Fall of Man