M45 shotgun

The M45 Tactical Shotgun is a shotgun used by the United Nations Space Command Army.

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.

Gameplay
In gameplay, the M45 Tactical Shotgun is more powerful than the M90 Close Assault Weapon System from Halo 3 and Halo 3: ODST. The rounds are packed closer when fired and the range is superior as well, which makes it harder to hit multiple enemies at close range.

Trivia

 * It is possible that Bungie named this shotgun the M45 because it is the in-game successor to the M90: 45 is half of 90.