From Halopedia, the Halo wiki
Post-Covenant War conflicts
The M8C Grindell/Galilean Nonlinear Cannon (M8C G/GNC) is a nose-mounted laser cannon that is equipped on the G79H-TC Pelican gunship.
In Halo 4 the HUD element for the M8C uses the M6 Spartan Laser aiming reticule.
The Hud of the G79 in Halo 4.