Here is a list of weapons which - so far - will make it's debut in Halo 4.
- U.N.S.C. weapons to be indroduced:
- Asymmetric Recoilless Carbine-920 (infantry-sized railgun weapon)
- BR85HB SR Battle Rifle "Battle Rilfe"
- M395 Designated Marksman Rifle "DMR"
- M363 Remote Projectile Detonator (A type of grenade/rocket launcher firing sticky explosives, pistol sized)
- MA5D Individual Combat Weapon System "Assault Rifle"
- Sniper Rifle System 99-S5 Anti-Material "Sniper Rifle"
- Unknown shotgun (No known designation)
- Covenant weapons to be introduced:
- Type-55 Directed Energy Rifle/Advanced Possibly an advancment of the Plasma Rifle "Storm Rifle"
- Forerunner weapons to be introduced:
- Light Rifle (no known official designation)
- Z-180 Close Combat Rifle/ Asymmetrical Engagement Migitator (A type of shotgun) "Scattershot"
Might i suggest, going to a Halowiki.
(^)The first post has enough info...