Almost all human weapons are mechanical in design and use some sort of metal based projectile to inflict harm such as bullets, grenades, or rockets. There are some exceptions to this such as the Spartan Laser which creates a powerful laser beam capable of burning through most defenses and heavy emplacements in a single shot or the new Rail Gun which has few moving parts and requires the creation of a magnetic field to propel it's ammunition.
These weapons tend to be common as starting weapons in online matches and in cases where the main character's weapons are reset during a campaign. This makes it important to know the ins and outs of these weapons for online play. During campaign play, it's not uncommon for ammunition for these weapons to become scarce but their general balance and utility makes them highly desirable during sections where you are unsure of what you'll encounter.
