From Halopedia, the Halo wiki
The M19 102mm high-explosive, shaped-charge surface-to-surface missile (M19 SSM) is a munition for the M41 SSR MAV/AW Rocket Launcher and M39 rocket turret employed on the back of the M12A1 Rocket Warthog.
The M19 SSM is capable of penetrating the heavy armor of even the Type-26 Wraith tank; lighter vehicles, such as the Type-32 Ghost reconnaissance vehicle, are typically destroyed upon impact. The M19's blast radius is rather large, making the projectile effective against concentrated groups of infantry.
HEAT warheads in missiles like the M19 use explosive fillers to collapse a cone of ductile metal, typically copper, in order to form a jet of metallic particles that expand toward the target at hypersonic velocities. The tip of the jet punches a small hole in the armor while the remainder of the jet that travels at slower speeds widens the hole and provides spall effect to whatever lies beyond the armor.
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