The MM-s3 grenade launcher was a long-range grenade launcher manufactured by Merr-Sonn Munitions, Inc.. The MM-s3 was frequently combined with the WW-676 repulsorlift sled to form a combined artillery system known as the MobileMortar-3. It may have been the final stage of the experimental Clone Wars MM(X) grenade launcher.
The launcher was primarily designed to fire the C-22 fragmentation grenade, although other grenades of similar size could be used instead. Grenades were fired at a rate of 50 rounds per minute and used an internal rotation module to stabilize their flight to maximum range. A sound dampener on the barrel allowed for silent firing, while a targeting computer gave range and fire-vector data. However its awkward position on the launcher meant many experienced gunners preferred to visually aim the weapon, saving the computer for use in low-visibility environments. An internal magazine could hold 12 grenades, while a motorized grenade pack carrying 100 grenades could be connect to the rear refill door. A microrepulsorlift assisted in transporting the MobileMortar-3 and negating most of the recoil in firing it.