Z-250 lightrifle

The Z-250 Directed Energy Engagement Weapon, also known as the LightRifle, is a Forerunner energy channel weapon.

Service history
The LightRifle is a precision weapon originally used during the human-Forerunner wars. Warrior-Servant marksmen utilized them in large sieges on human redoubts. The weapon served well against the humans' particle rifles. The Ur-Didact's Promethean Knight units encountered on Requiem and on Installation 03 utilized the Z-250. A small number of Sangheili members within Jul 'Mdama's Covenant faction also utilized the Z-250 during the Second Battle of Requiem.

Design details
It is a scoped, mid-range to long-range weapon that normally fires a three-shot burst or a powerful concentrated semi-automatic shot which consumes three units when zoomed in. It holds 36 units per magazine however this provides 12 shots. It fires luminescent orange hardlight rounds. Functionally, the weapon employs componential particle acceleration to fire beams of hard light particles at a high speed and accuracy. . Using the diffused combination of particle acceleration and hardened photonic matter, it fires fast and accurate beams which are capable of dropping individual enemies in a few well placed shots.

The rifle possesses an angular design and metallic casing. It features a stock, a firing grip, a stabilizing firing grip, a scope and a light mass channel. It appears to be held together, at least partly, by energy fields as indicated by its self-assembly process and floating sights. Orange lights are present while the weapon is self-assembling and throughout the casing once assembly is complete; there is also a column of orange-colored energy that runs through the light mass channel. Hard light highlights stream along the sides of the weapon while it is fired. The sight through the scope is tinted orange and is approximately a 4x zoom. It features integrated targeting optics.

Barbed Lance
The Barbed Lance is an improved Z-250 with faster rate of fire and larger magazine.

Dying Star
The Dying Star is an advanced Z-250 designed for combat against Flood pure forms. It fires adhesive pulsewave explosives; three nearby explosions will prove fatal to even a shielded Spartan.

Halo 4
In Halo 4 the rifle is essentially a mix between the Battle Rifle and the DMR in that it possesses the three-round burst of the BR while not scoped-in and the single-shot fire of the DMR when scoped in. While its burst-fire function isn't as potent as that of the Battle Rifle's, its semi-automatic fire is much more powerful than that of the DMR's, thus outclassing the two while zoomed in, especially from a distance with its higher 4x zoom magnification. However, it is slightly hindered by a slower firing rate compared to the two other weapons making it critical that the shots land and result in a headshot. While the time to kill of the unscoped mode is higher to both human weapons, the scoped mode has a lower time to kill. At the maximum red reticle range, the LightRifle can easily overpower a DMR or a BR. While it is not as suitable for close ranges, an extremely skilled user can utilize both firing modes to achieve a lower kill time than its human counterparts.

While unscoped, three shots are required to leave an opponent vulnerable to a single lethal melee. Two shots of the single fire mode are required to achieve the same effect. The magazine has two different displays in the HUD: 36 small rounds for unscoped mode and 12 rounds for scoped.

Halo 5: Guardians
In Halo 5: Guardians the lightrifle is no longer capable of a three-round burst like the battle rifle. The weapon remains aesthetically similar to its Halo 4 version with a change to the scope.

Changes from Halo 4 to Halo 5: Guardians

 * Unscoped mode now fires a single round (similar to the Halo 4 versions scoped firing style) instead of bursts, taking 4 shots to kill a fully-shielded Spartan if the last shot is a headshot.
 * Scoped mode now fires a flat, wide projectile, which takes 3 shots to kill provided the final shot is a headshot.
 * It features a reduced zoom.
 * Ammunition capacity is reduced to match the new single-shot only firing mode.
 * Features Smart Scope capability.

Trivia

 * The Lightrifle was originally conceptualized as the Binary Rifle in the preliminary phase of development.
 * Some Sangheili warriors in Spartan Ops are seen wielding lightrifles, as well as Scattershots. Presumably the taboo on using human weaponry observed during the Human-Covenant War does not extend to Forerunner weaponry, perhaps because of the Covenant's veneration of Forerunners and their technology, or that this particular group of Elites (as part of Jul 'Mdama's Covenant faction) does not share either taboo.
 * The weapon's fire rate was lessened and its damage was increased during the 'turbo update', making it different in campaign and multiplayer.
 * Getting a perfect kill with the lightrifle in Halo 5: Guardians multiplayer rewards the player with a medal unique to the lightrifle.

List of appearances

 * Scanned
 * Halo 4
 * Terminals
 * Spartan Ops
 * Halo: Escalation
 * Halo: Hunters in the Dark
 * Halo 5: Guardians