M45 shotgun

The M45 Tactical Shotgun, formally known as the Tactical Shotgun, 8 Gauge, Pump Action, M45, is a shotgun used by the UNSC Defense Force. It is manufactured by Misriah Armory.

Overview
The M45 is the most widely used shotgun in service with the UNSC Defense Force, being more common than the M90 Close Assault Weapon System. It was used throughout the Insurrection and later the Human-Covenant War. The M45 is used during most close-combat scenarios, particularly in urban areas with heavy enemy occupation.

Design details
The M45 Tactical Shotgun is a special-purpose weapon used in any situation where the range of engagement is limited and when over-penetration is not desirable, but maximum stopping power is required. Like the functionally identical M90A Close Assault Weapon System, the M45 is a pump-action, magazine-fed (dual tubular, non-detachable type) weapon that uses 8 gauge magnum (3.75”) ammunition. The standard M45 features a six-round magazine, though the M90E features a twelve-round magazine akin to that of the M90 CAWS. The M45's factory-default sights are colored red.

M45E Tactical Shotgun
The M45E is a variant of the standard M45 Tactical Shotgun. The E variant performs identically to the M90 Close Assault Weapon System, featuring greater stopping power and longer range than the standard M45, despite having a shorter barrel than the M90. Also like the M90, the M45E features blue sights rather than the red sights featured on the standard M45.

Halo: Reach
In gameplay, the M45 Tactical Shotgun is more powerful than the M90A Close Assault Weapon System from Halo 3 and Halo 3: ODST. The pellets have a tighter grouping and the range is superior as well, which also makes it harder to hit multiple enemies at close range. Although this change is hardly noticeable, impact force can be noticed as damage is higher.

The shotgun is very powerful in small confined maps. It should be used as a "corridor sweeper" because of its extreme damage at close range. When you are carrying this weapon people will mark you out as an important target due to the fact that you control a power weapon.

Halo: Combat Evolved Anniversary
In Halo: Combat Evolved Anniversary, the M45E is used in lieu of the M90 CAWS featured in the original game. As the changes between the original weapon and its replacement are superficial (both canonically and in gameplay), the weapon performs identically to the M90 in Halo: Combat Evolved.

Trivia

 * It is possible that Bungie named this shotgun the M45 because it is the in-game counterpart to the M90 from the other games: 45 is half of 90.
 * In the Halo: Reach Multiplayer Beta, the shotgun had cyan lights similar to those on the M90. The sights are red in the final game.
 * In Halo: Reach, the M45 is pumped at the end of every reload animation; similarly, when a Sangheili character draws this weapon, they cycle the action. In reality, doing this when the weapon is not empty would eject an unused shell.
 * In the Halo: Reach strategy guide, the silhouette used to mark shotgun spawns points on multiplayer maps appears to be missing their stocks. However, the M45 does not feature collapsible stock does not appear in the final version of the game.
 * In the second issue of Halo: Fall of Reach - Boot Camp, the captain of the retrieves several shotguns from a cryo chamber. In the first two panels, the shotguns appear to be M45s, though they resemble M90s in subsequent panels.

List of appearances

 * Halo: Reach
 * Halo: Combat Evolved Anniversary
 * Halo: Fall of Reach - Boot Camp