M7 SMG

"I’ve seen a Spartan use two at once, tearing the crap out of the little ones; sending the big ones down in bloody heaps. But I guess that’s what ya gotta be to pull it off: an action-movie hero or a seven-foot-tall walking tank."

- Anonymous E2-BAG/1/7 serviceman

The M7/Caseless Submachine Gun is a personal defense weapon developed and manufactured by Misriah Armory, commonly used by infantry, special forces, and vehicle crews of the UNSC Defense Force. A suppressed version of the weapon, the M7S SMG, is often issued to special operations personnel.

Design details
The M7/Caseless Submachine Gun is an automatic submachine gun that fires from a 60-round magazine which is placed horizontally on the left side of the weapon. Due to the odd horizontal placement of the magazine on the weapon, it can be assumed that the magazine utilizes a circular ramp where the magazine meets the breech. This rotates the horizontally stacked rounds in the magazine 90 degrees until they align with the horizontal breech. An example of this can be seen in the present day Fabrique Nationale P90 SMG.

The SMG has a polymer pistol grip, folding fore-grip, iron sights, and collapsible buttstock, as well as a titanium body. The SMG must be cocked before it can fire the first round. The charging handle is located on the right side of the gun and does not move during operation. Once the first round is fired, the gases from previous rounds force the breech to rotate and chamber a new round. Once the magazine is empty, the handle although not illustrated in-game, can either be pulled back and locked or it can be fully cycled after a fresh magazine has been housed. If it is first pulled back and locked, then it must be pushed forward in order to chamber a new round. The magazine release button is located between the red dots on the receiver and needs to be pressed before it can be flicked off. There is no ejection port due to the nature of the rounds fired.

The SMG has a rifled barrel that is 15 cm (5.9 in.) long. This weapon can also be affixed with a suppressor; in this configuration, the weapon is designated the M7S Caseless Submachine Gun. The weapon is 47.4 cm (18.66 in.) long with the stock retracted. The stock is always retracted in-game and has a maximum length of 62.7 cm (24.68 in.) when the stock is fully extended.

Ammunition
Unlike most UNSC weapons, the M7 uses caseless 5x23mm ammunition, meaning it does not have a metallic casing surrounding the powder and sealing the bullet, propellant, and primer together. Instead of using this casing, the round uses a combustible adhesive to seal these components together. Because the adhesive and propellant are both vaporized when fired, there is no need to eject spent casings. Though not featured in-game, contemporary caseless ammunition is highly susceptible to cook-off, the accidental firing of rounds due to built-up heat in the receiver.

This feature is very beneficial. In addition to increasing fire rate by removing the extraction and ejection phases of the weapon's cycle, it reduces friction inside the magazine, one of the main causes of malfunctions in weapons. This is also conducive to dual-wielding, since the user need not concern themselves with hot brass expelled from the weapon held in the left hand. The projectile itself is jacketed in metal, usually a copper alloy in standard military ammunition, to aid in penetration of the target. Caseless rounds are actually embedded into the block of propellant, reducing their length, allowing more ammunition to be stored in a smaller space.

Advantages
Nicknamed the "bullet-hose", the SMG is one of the best close-quarters firearm due to its large 60-round magazine and hit-scan properties. Suited for close-range combat, the SMG is extremely deadly against unshielded targets and can down shielded targets within seconds if dual-wielded.

The SMG can also form part of the most effective dual-wield combos in the game. The SMG, when dual-wielded with a Type-25 plasma rifle, can be a deadly combination as the plasma rifle depletes the opponent's shields with ease and the SMG rapidly tears through their health. Similar deadly combination, often referred to as the "noob combo", is dual-wielding the SMG and Type-25 plasma pistol. The charged shot from the plasma pistol will deplete the shield of the opponent and a full burst of SMG fire will tear through the now-exposed flesh and armor.

Disadvantages
As aforementioned above, the SMG received the nickname "the Bullet-Hose" due to its high rate of fire, low accuracy, and inability to be fully controlled when fired in full-auto. The SMG's primary limiting factor is its poor accuracy, which limits its use to close range. At close-quarters combat, the SMG is only outperformed by the M90 shotgun, the Type-1 energy sword, and the Type-2 gravity hammer. Like most other human weapons, the SMG performs relatively poorly against shields, though this weakness is negated by wielding it in conjunction with a plasma rifle or plasma pistol. As stated before, the gun has recoil which causes the barrel to climb after continuous fire and will climb faster if players dual-wield it. This forces the players to continually move their reticule down to keep the enemy in their sights but is not a big limiting factor. This, as well as the poor accuracy can be slightly countered, using a burst-fire technique, unleashing about five bullets each pull of the trigger. It also has the problem of an extremely long reload time when dual-wielded, making it easy to be killed while changing magazines. This problem however can be solved by volley firing the weapons, so while one is reloading the other is still firing. This tactic reduces the power of having two SMGs but gives the advantage of approximately 40+ seconds of non-stop firing.

Changes from Halo 2 to Halo 3

 * Increased accuracy, range, damage and rate of fire
 * There is now a delay before the barrel actually starts to climb.
 * When dual-wielding SMGs, the weapons are held farther from the body.
 * The player's reserve ammunition capacity is reduced.

UNSC remarks

 * “The recoil isn’t bad but the M7 itself is relatively light. Not unpleasant to shoot, but a little tricky to control—it’s all about controlling the impulse.”
 * “It’s actually comparable in weight to the M6 — favorably, in fact. That and not having to worry about the hot casing dropping down on your boot makes it a pretty clear choice which one I think is the better system.”
 * “Yes; I have fired it one-handed with the stock collapsed and the foregrip folded. No; I was not driving at the time, I was shotgun. Did I hit anything? Don’t know—probably never will—no more bogeys afterward, though.”
 * “It’s not a death ray but nobody likes getting shot. Not even Bravo Kilos. And you can fill the air with a lot of lead with an M7."
 * “The M7 is the wave of the future. Hopefully the Romeo Echo Mike Foxtrots will finally realize the benefits of caseless ammunition.”
 * "I’ve seen a Spartan use two at once, tearing the crap out of the little ones; sending the big ones down in bloody heaps. But I guess that’s what ya gotta be to pull it off: an action-movie hero or a seven-foot-tall walking tank."

Trivia

 * In Halo 2, when the player wields a single M7, the SMG's stock is extended. When the M7 is dual-wielded, the stock is collapsed. In Halo 3, the stock remains locked halfway in both the first-person and third-person animations, regardless of whether the weapon is being dual-wielded.
 * The M7 SMG is depicted as ejecting shell casings in "Monsters" cutscene from Halo Wars and in the Halo Legends short The Babysitter. The cutscene shows ejected casings in only one instance, while in other shots the weapon's operation is correctly depicted; however, the short features a lingering shot on Dutch's spent brass. This is an artistic error as the M7 does not have an ejection port to remove spent casings, compounded by the weapon's very name describing it as caseless. When this discrepancy was brought up on the halo.bungie.org forums, Frank O'Connor replied that there is a cased variant of the weapon. Despite this, the small frame of the weapon and its magazine makes it unlikely that such a version exists.
 * The circular ramp the M7 uses to feed rounds into the chamber is similar to the mechanism utilized in the real-world FN P90 submachine gun. However, the P90 uses a top-loaded magazine that feeds cased 5.7x28mm rounds horizontally.

List of appearances

 * Halo: First Strike
 * Halo 2
 * Halo Graphic Novel
 * Armor Testing
 * Halo: Ghosts of Onyx
 * Halo: Uprising
 * Halo 3
 * Halo: Contact Harvest
 * Halo: The Cole Protocol
 * Halo Wars
 * Halo: Helljumper
 * The Life
 * Halo 3: ODST
 * Halo Legends
 * Prototype
 * The Package
 * Origins
 * Halo: Evolutions - Essential Tales of the Halo Universe
 * Dirt
 * Halo: Blood Line
 * Halo: Spartan Assault
 * Halo 2 Anniversary
 * Halo 5: Guardians