Base Weapons
Assault Rifle - Spray weapon, good damage, good range, best for mid-short range engagements
Battle Rifle/H2BR - Precision weapon, good damage, good range, best for mid range engagements
SMG - Spray weapon, very high damage, very short range, best for close range engagements
DMR - Precision weapon, very high damage, long range, best for long range engagements
Pistol/Magnum - Precision weapon, high damage, close range, best for short-mid engagements.
Attachments
Extended mag - Larger magazine and ammo pool
Long Barrel - increased range (crosshair will go red and enable bullet tracking at longer ranges)
Suppressor - you firing won't appear on motion tracker and harder for enemy to hear
stabilization jets - reduced recoil
Laser Pointer - increased accuracy (better bullet tracking)
Kinetic Bolts - increased vehicle damage, increased flinch
energy bayonet - increased melee damage and range (one hit kill in most situations)
hardlight bayonet - increased melee damage and range, increased vehicle damage
Sights
Recon - 2x (default on battle rifle)
longshot - 3x (default on DMR)
Sentinel - 4x-6x
Projection - 1.5x (default on Magnum and AR, only SMG can also unlock)
Carbine - 2x (same as Covenant Carbine)