From UFStarfleet Wiki
The M-78 is often compared to the old Earth shotgun. It fires a burst of energy that hits a large area but unlike most phasers the effective distance is very short.
The M-78 first used by Lt.Commander Munro of the Hazard Team when aboard the Enterprise and has been adapted for use by the Marines.
The M-78 has two primary setting burst and spray. Burst is the energy being released in a large explosion which is much more powerful then a singe shot from any phaser. Spray is the same energy being divided up into many small individual beams and is very effective against large groups of people. Even after several upgrades it still has a high power consumption so is only issued on an as needed bases.
- Mark I - Prototype
- Mark II - First Production Model
- Mark III - Adaptation for Marine use
- Mark IV - Modification to decrease power consumption.