Light machine gun – The 556 Icarus is a lightweight squad-support weapon in the M4 platform. Increased ammo capacity does not significantly impact mobility.
| Level | Unlock | Type |
| 2 | Underbarrel category | Equip underbarrel attachments to this weapon |
| 3 | Muzzle category | Equip muzzle attachments to this weapon |
| 4 | FTAC Coldforge 16” Barrel – barrel | M4 platform attachment |
| 5 | Optic category | Equip optic attachments to this weapon |
| 6 | 100 Round Box Mag – magazine | M4 platform attachment |
| 7 | Laser category | Equip laser attachments to this weapon |
| 8 | Demo Precision Elite Factory – stock? | M4 platform attachment |
| 9 | Forge Tac Delta 4 – optic | Universal attachment |
| 10 | FTAC Castle Comp – muzzle | Universal attachment |
| 11 | Rear grip category | Equip rear grip attachments to this weapon |
| 12 | FTAC SB – barrel | M4 platform attachment |
| 13 | M16 – receiver | New weapon |
| 14 | VX Pineapple – underbarrel | Universal attachment |
| 15 | Ammo category | Equip ammunition attachments to this weapon |
| 16 | Weapon tuning | Fine-tune attachment performance on this weapon |