The UA 571-D Ground Sentry was a 12mm anti-aircraft artillery emplacement manufactured by Weyland-Yutani.
Malcolm Reynolds, a sergeant for the Independent Planets, used one of these emplacements to shoot down an Alliance skiff during the Battle of Serenity Valley.
Behind the Scenes[]
The weapon appears to be the dual DShK (likely mocked-up M2 Browning) AA machine gun emplacement used in Starship Troopers.
The Insignia for the Weyland-Yutani Corporation is visible on the weapon. The weapon's name itself is a reference to the UA 571-C Automated Sentry Gun featured in the 1986 film Aliens.