From Halopedia, the Halo wiki
- Roland Huffman and Niraj Shah join the UNSC Armed Forces.
- The M392 Designated Marksman Rifle, having been steadily phased out in favor of the BR55 Service Rifle for some time, is replaced by the BR55 Heavy Barrel Service Rifle in all branches but the Army.
- The Covenant launch their first attack on the Outer Colony of Meridian; the UNSC are successful in repelling this attack.
- The MJOLNIR Powered Assault Armor/CQC variant enters service.
- The Battle of Algolis occurs during or after this year.
- Bungie.net: Halo 3: ODST Field Guide - Personnel
- YouTube: Halo 3 - Official "Enemy Weapon" Film
- Halo Waypoint, DMR
- Halo: Reach - Armory
- One of the Marines at the Battle of Algolis used a BR55HB Service Rifle. As this weapon was introduced in 2548, the battle must have taken place during or after this year.