M57 Pilum

The M57 Pilum is a is a portable single-shot light anti-tank weapon used by the UNSC. Designed as a cheaper, disposable alternative to the M19 Jackhammer, the Pilum fires M29 50mm HEDP rockets.
One well-documented instance of use by Special Forces occurred on Jericho VII in 2535, when two were used by Kelly-087 to destroy a pair of Type-26 Shade turrets in an ambush on Covenant rearguard forces during Operation: FALLEN WALLS.