HALOS (Hyboria)

Rifle, 48-inch, M8
3 examples shown on Barbette Mount M13
Type	Low-orbital hypervelocity asteroid interception and air and ballistic missile defense
Place of origin	Hyboria
Service history
In service	1987-
Used by	Hyboria
Wars	Omandan Continental War
Production history
Designer	Dr. William Atkinson
Designed	1970
Manufacturer	Various
Unit cost	20 Billion dollars
Produced	1982-1990
No. built	8
Specifications
Shell weight	12 tonnes
Caliber	1,200 mm (47 in)
Elevation	+80° -15°
Traverse	360°
Rate of fire	1 round every 5 minutes
Muzzle velocity	6 km/s (20,000 ft/s)
Effective firing range	1,500 km (930 mi)
Maximum firing range	2,000 km (1,200 mi)
References

The Hyborian Anti Low Orbital System, also known as HALOS or by its project name, Project Stonehenghe is a low-orbital hypervelocity asteroid interception and strategic air and ballistic missile defense system developed and built in Hyboria. The system was developed initially to combat low-orbital debris and asteroid impacts following the planetfall of the Ulysses Asteroid in the 1910s and subsequent years following. During the events of the Omandan Continental War its use as an anti-air and missile defense system was also unveiled. Upon entry in early 1987, the HALOS was used against a large formation of Transnapistani bomber aircraft using a low-yield nuclear munition, the existence of which had been kept a secret to the world. The guns would go on using their standard ammunition for engagements until the 1994 nuclear exchange. Then the system would also show its use as a ballistic missile defense system, shooting down Transnapistani MRVs with their low-yield nuclear shells, greatly reducing effectiveness of the nuclear strike on Hyboria.

It is the largest artillery gun in the world, uses the largest supercomputer in the world and is the only major operational light-gas gun in service in the world.

Ammunition

• Projectile, 48-inch: Test, M800: Initial test projectile used in the mid-1980s. M800, M801, M802 and M803 were all test projectiles used to prove the design
• Projectile, 48-inch: Test, M801
• Projectile, 48-inch: Test, M802
• Projectile, 48-inch: Test, M803
• Projectile, 48-inch: Dummy, M804: Training munition used in cycling the reloading system, based on final design of the M803
• Projectile, 48-inch: High-Explosive Asteroid-Penetrating, M805 (HEAP): First model shell used to engage asteroid fragments, used to a limited role against massive aircraft formations. Improved into the M805A1 model. Replaced by the M807 I-HEAP round. Used in over 129 interceptions of asteroid fragments.
• Projectile, 48-inch: Artillery Fired Atomic Projectile, M856 (AFAP): First type of nuclear munition developed, used the W56 warhead with a 1.2 megaton yield. Was considered for use in both anti-air, BMD, and also in the anti-ground role. Was never used, less than 20 produced and all decommissioned by 2010. Designation of M856 was given as it used the W56 warhead.
• Projectile, 48-inch: Artillery Fired Atomic Projectile, Anti-Aircraft, M862 (AFAPAA): Used the W62 thermonuclear warhead with a yield of 170 kilotons. Used multiple times during the OCW. Total number produced is classified, possibly over 400 rounds. Production is ongoing with the improved M862A1, taking advantage of improvements applied to M807.
• Projectile, 48-inch: Atmospheric Testing, M806 (AT): Used for atmospheric testing experiments.
• Projectile, 48-inch: Improved High-Explosive Armor-Piercing, M807 (I-HEAP): Improved model of shell produced by the end of the OCW, did not see service during. Current in-production shell.
• Projectile, 48-inch: High-Explosive Armor-Piercing, Rocket-Assisted, M808 (HEAPRA): New shell in development or already in service, range is reported to be "greatly extended".