The Heavy Machine Gun Turret is a powerful gatling-style machine gun, first seen as only an attachment to the Warthog early on in the series. It is one of the most recurring weapons in the series.
- Simmons: Simmons uses the turret on the warthog throughout the series since 1.21 Giga-Whats??. He would later kill several Wyoming clones and two Recovery agents using this weapon.
- Red Zealot: When the Reds and Blues attacked O'Malley's fortress, the Zealot manned a turret, suppressing the team using the weapon with Lopez before he was killed by Tucker.
- Lopez: Along with the Zealot, Lopez manned a turret (as only a head) to suppress the Reds and Blues before he was shot off the turret by Tex.
- Washington: In Reconstruction: Chapter 11, Wash ambushes Meta with a heavy machine gun turret, but the Meta survives due to his overshield and escapes using his time distortion unit.
- C.T.'s Men: It was used by the Aliens and C.T.'s men during Recreation.
- Epsilon-Tex: In Reunion, Epsilon-Tex used a hidden heavy machine gun to fire at the Meta.
- Demo Man: The Demo Man uses the turret to capture Freelancers North and South.
- Carolina: When the Demo Man captured North and South, Carolina appeared and disarmed him. She then used it to fire upon the other Insurrectionists.
- Chain Guy and Chain Girl: The heavy machine gun turret is used again in Fighting Fire by the two insurrectionist chain gunners to suppress the Freelancers. However, they were killed by Agent Florida during their assault.
- Sarge: When Sarge over reacted about Simmons staying with the Blues in A House Divided, Then Multiplied, Sarge manned the warthog's turret to attack the Blues. However, he's nearly killed by Freckles when Sarge began to use the turret, resulting in the vehicle being destroyed. He also used it in Armonia, Part 2 to defend against Space Pirates.
- Tucker: In Fire, after Washington leaves to assist Simmons, Tucker mans the turret during Wash's absence.
- Red Fed: The Heavy Machine Gun Turret is the Red Fed's primary weapon of choice.
- Much like the rocket launcher, despite being one of the most powerful weapons in the series, only two characters (Simmons and Carolina) have used the weapon successfully to kill another character.