From Halopedia, the Halo wiki
|M340 40mm autocannon
This chaingun fires 40mm ammunition.
The 40mm chaingun was a weapon employed on Pelican dropships prior to around 2525. By this time, the chaingun had been superseded by the M370 70mm autocannon. By 2525, a Pelican equipped with such a weapon was docked in the United Rebel Front stronghold of Eridanus Secundus. The weapon is also employed on Condor dropships such as the G81 variant. Although military Condors keep the chain gun, civilian models eschew it and all fire control systems.
In the Halo Legends short Homecoming depicts a D77-TC Pelican dropship armed with a nose-mounted weapon unlike the M370 70mm autocannon depicted as standard on most Pelican dropships, which may possibly be the 40mm chaingun. However, the short takes place far in the Human-Covenant War, long after the time period in which the 40mm chaingun is said to have been retired. It is possible that the 40mm chaingun retained in service in back-line units and older garrisons, and thus continued to see sporadic usage in the later years of the war.
The Halo Encyclopedia (2022 edition) establishes that the G81 Condor employs a chin-mounted M340 40mm autocannon, and is built on the elongated fuselage of older Pelicans. The M340 additionally is set before the M370 in its designation, which concurs with the note in The Fall of Reach that the 40mm models were replaced by the newer cannons like the M370. As such, it can be reasonably inferred that this 40mm chaingun is the same as the one mentioned in The Fall of Reach.
List of appearances
- Halo: The Fall of Reach (First appearance)