ALI-50 110mm autocannon

The 110mm Rotary Cannon is a projectile weapon equipped to the C709 Longsword Interceptor, essentially a giant minigun firing 110mm shells and used to engage enemy fighters or starships.

Trivia

 * According to Robert McLees, the concept of "110mm rotary cannons in fighter/bombers" is considered "bad crazy" in the Halo Story Bible, seemingly implying that the weapon's unusually high caliber is considered a typo.