Infantry Weapons

GAU-18/A machine gun

Also known as

GAU-18
GAU-18A
GAU 18/A
GAU-18/A .50 caliber machine gun

The GAU-18/A is a U.S. .50-caliber helicopter machine gun in the Browning M2/M3 family. Air Force testing ties it to HH-60W rescue-helicopter armament, and FN's EMGS system supports window-mounted installation on that airframe.

GAU-18/A machine gun, .50 caliber machine gun, Infantry Weapons

Image source: GAU-18A .50 caliber machine gun [Image 6 of 7]

Profile / Specs

Profile

Origin: United States
Built by: BrowningU.S. military contractors
Type: .50 caliber machine gun
Service note: Cold War to present helicopter armament
Designer: John M. Browning

machine gun heavy machine gun aircraft armament helicopter belt-fed

Specifications

Caliber: 12.7x99 mm NATO / .50 BMG
Action: Single-barrel, close-bolt, air-cooled
Feed: Left-hand feed and right-hand charging; HH-60 EMGS installs use a feed chute from external ammunition containers
Rate of fire: 650-850 rounds per minute
Mounting: Helicopter window or door-gun installation on HH-60 and MH-53 aircraft

Compatible Helicopters

FN Herstal's HH-60W EMGS material says the unmodified GAU-18/A can be installed on HH-60W windows.

Compatible item

Item type

Compatibility evidence

HH-60W Jolly Green II, Combat rescue helicopter, Aircraft & UAVs

HH-60W Jolly Green II

Combat rescue helicopter

FN Herstal says the HH-60W windows can install the GAU-18/A machine gun through the external mounted gun system.

Sources: FN HH-60W EMGS, FN EMGS

Service And Conflict Use

Service History

In service: Used on USAF MH-53 Pave Low and HH-60 Pave Hawk helicopters; FN's EMGS material shows HH-60W window integration for the unmodified GAU-18/A.
Used by: United States Air Force

Media

GAU-18/A machine gun Images

GAU-18/A machine gun, .50 caliber machine gun, Infantry Weapons - view 1 — Source: GAU-18A .50 caliber machine gun [Image 6 of 7]

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Sources

Tinker live-fire testingPublisher: Tinker Air Force Base | Note: Supports the GAU-18 as a .50 caliber legacy machine gun, its close-bolt air-cooled description, and the 650-850 rpm fire-rate range used in HH-60W testing. | Accessed: 2026-06-27 FN HH-60W EMGSPublisher: FN Herstal | Note: Supports the EMGS mounting interface that installs third-party GAU-18/A guns on HH-60W windows. | Accessed: 2026-06-27 FN EMGSPublisher: FN Herstal | Note: Supports the external mounted gun system, its GAU-18 compatibility language, and HH-60W operational use. | Accessed: 2026-06-27 GAU-18/A excerpt | Oliver Hazard Perry Class Frigates 2015Publisher: Internet Archive | Note: Supports the GAU-18/A as a lightweight variant of the M2/M3 family, its left-hand feed/right-hand charging setup, and its helicopter installation context. | Accessed: 2026-06-27 GAU-18A .50 caliber machine gun [Image 6 of 7]Publisher: DVIDS | Note: Supports image provenance for the GAU-18A on an HH-60G Pave Hawk. | Accessed: 2026-06-27 Cope Angel 2025: U.S and Japan sharpen search and rescue skills [Image 11 of 16]Publisher: DVIDS | Note: Supports image provenance for the GAU-18/A on an HH-60W Jolly Green II. | Accessed: 2026-06-27