The stated mission of the Marine Littoral Regiment centers on conducting Expeditionary Advanced Base Operations. This means they’re built to establish and operate small, forward, expeditionary bases near contested littoral zones to enable distributed, scalable operations in the near-shoal environment. These bases would support naval maneuver, logistics, fires, and reconnaissance across a wider area without relying on large, fixed installations. Humanitarian relief is important but not the MLR’s primary stated mission. Stealth reconnaissance and anti-submarine warfare are specialized tasks more aligned with ISR-focused or naval warfare units, not the core role of the MLR. So the Expeditionary Advanced Base Operations capability best matches the MLR’s official mission.

Mortars deliver indirect fire with a high-arcing trajectory, designed to hit targets that aren’t in the line of sight. The 60 mm mortar’s role is to provide sudden, sustained suppressive fire on areas where enemies may be hidden behind cover, trenches, or terrain features, allowing friendly troops to maneuver safely. This high-angle fire can reach over obstacles and into concealed positions, which direct-fire weapons can’t easily strike. The emphasis is on keeping the enemy under pressure and denying them freedom of movement, not on precise single-target shots. The other described roles rely on low-angle direct fire or specialized weapons (moving vehicles, anti-tank, or air defense), which aren’t how this lightweight mortar is used.

The key idea is recognizing the MSGL as a compact, handheld grenade launcher that uses a revolving cylinder to fire multiple rounds. It’s designed as a lightweight, six-shot system, firing 40 mm grenades from a revolver-type chamber. This distinguishes it from belt-fed automatic launchers, which would be a different design, and from mortars or rifles, which are not under-barrel grenade launchers. So the description that matches is the one describing a lightweight 40 mm six-shot revolver-type grenade launcher.

Bearings used in navigation can be true (geographic) or magnetic (compass). The Earth’s magnetic field is not aligned with true north, so the offset at your location—magnetic variation or declination—must be applied to your bearings to use them correctly. To convert, apply the variation to the bearing you’re working with: if the variation is east, subtract it to get the magnetic bearing; if it is west, add it. For example, a true bearing of 030° with a variation of 10° East becomes a magnetic bearing of 020°. If the variation is 10° West, the magnetic bearing would be 040°. Variation changes with location and over time, so check current values on charts and update your calculations accordingly. Note that this is different from compass deviation, which is caused by the vessel itself.