Z-250 lightrifle

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

Design details
The lightrifle fires luminescent orange hardlight rounds. It is a scoped, mid-range to long-range weapon that normally fires a three-shot burst with one pull of the trigger. When zoomed in, however, it fires a single high-powered concentrated shot that consumes three units of ammunition. It holds 36 units per magazine; however this provides 12 shots while zoomed in. Functionally, the weapon employs componential particle acceleration to fire beams of hard light particles at a high speed and with pinpoint accuracy. Using the diffused combination of particle acceleration and hardened photonic matter, it is capable of dropping individual shielded enemies such as Elites, Spartans, Promethean Knights, and Promethean Soldiers 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 4× zoom. It features integrated targeting optics. The Light Rifle was manufactured and developed by Ferrarius Assembler Vats.

Operational 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. Armigers stationed on Installation 00 used lightrifles against human and Sangheili forces during Operation: FAR STORM. 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 and Spartan-IVs aboard the also utilized the Z-250 during the Requiem Campaign. It is ranked a Rare REQ in Warzone simulations, and is available at Level 4 energy while giving 100 REQ points if sold. During the Mission to Mount Kilimanjaro, 343 Guilty Spark used in a Z-250 in his armiger body to bring down a rocky overhang on Fireteam Apollo and an ONI team as a distraction to help the Ace of Spades crew to escape. As Spark was only aiming for a distraction, no one was seriously hurt and the crew managed to escape using a translocation pad.

Variants

 * Barbed Lance: The Barbed Lance, an improved Z-250 with faster rate of fire and larger magazine carrying up to 16 rounds, is classified as an Ultra-Rare REQ in Warzone simulations and available at Level 4 energy while giving 150 REQ points if sold.
 * Dying Star: The Dying Star, an advanced Z-250 designed for combat against Flood pure forms, fires adhesive pulsewave explosives; three nearby explosions will prove fatal to even a shielded Spartan. The Dying Star's explosive rounds also disintegrate enemies upon landing a killing blow. However, it has a reduced magazine size of 8 rounds as opposed to 12. In Warzone simulations, the Dying Star is a Legendary REQ that requires Level 5 energy.

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 former while not scoped-in and the single-shot fire of the latter 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 4× 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. The maximum ammo one can carry is 36/108 when unscoped or 12/36 if scoped.

Halo 5: Guardians
In Halo 5: Guardians the LightRifle (as it is now capitalized) is no longer capable of a three-round burst like the battle rifle, and instead fires single shots like its Halo 4 rendition's scoped-in mode. The weapon remains aesthetically similar to its Halo 4 version with a change to the scope and a pair of cylindrical components under-slung near the muzzle. However, utilizing the smart scope on the weapon now causes the beam to spread out slightly, allowing for easier hits on moving or distant targets, and reduces the required shots to kill from four to three, assuming the final round is a headshot. Its fire rate drops dramatically while scoped however, making landing that final round more difficult than would be expected. In gameplay, it is significantly harder to find, as there are fewer Prometheans using them than in Halo 4, also due to the fact that Promethean Soldiers can switch to Suppressors if players get too close to them.

Changes from Halo 4 to Turbo update

 * The rate of fire of the Lightrifle has been increased when zoomed in.
 * The rate of fire of the Lightrifle has been decreased when zoomed out.
 * The red reticle range of the Lightrifle now matches the DMR's Turbo-era range.

Changes from Turbo to Halo 5: Guardians

 * Unscoped mode now fires a single round (similar to the Halo 4 version's scoped firing style) instead of three-round 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.
 * Zoom significantly reduced.
 * Ammunition capacity is adjusted to match the new single-shot only firing mode from 36/108 to 12/36.
 * Name is now capitalized as LightRifle.
 * Rates of fire when zoomed out and zoomed in are slightly reduced.

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.
 * 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
 * Halo Mythos
 * Halo: Bad Blood
 * Halo: Renegades
 * Halo: Point of Light
 * Halo: Outcasts