M7/Caseless Submachine Gun

"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."

The M7/Caseless Submachine Gun, more simply known as the SMG, is a United Nations Space Command infantry and special operations weapon. There is also a version, the M7S Submachine Gun, which is equipped with an external suppressor to reduce the sound of the gunshots and reduce the flash from the muzzle, combine this with the light weight, and this gun becomes the weapon of choice for stealth operations.

Design Details
The M7/Caseless Submachine Gun is an automatic UNSC 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, as well as the HK G11 experimental assault rifle, both of which utilized a vertical loading system. The HK G11 also used caseless rounds like the M7. It also has various points which it resembles the Heckler and Koch MP7, such as the name, foregrip, frame of the weapon, retracting stock, etc.

The SMG has a polymer handle, folding fore-grip, iron sights, and retractable stock, 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 called the M7S Submachine Gun. The weapon is 47.4 cm (18.66 in.) long with the stock retracted. The stock is always retracted in games, and has a maximum length of 62.7 cm (24.68 in.) when the stock is fully extended. The stock is also fully adjustable.

Ammunition
The SMG uses 5 x 23mm caseless ammunition, a radically different kind of ammunition than the kind found in other UNSC weapons. This ammunition is classified as "caseless," 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 jamming 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.

The SMG's 5x23mm (.197 caliber) rounds, while smaller than most other SMGs, could classify it as a PDW (Personal Defense Weapon), which it has already taken several design forms.

Advantages
The SMG is an excellent suppressive weapon in Campaign against an unwitting AI or at close range in Multiplayer. It is also works well against swarms of Flood. The guns rate of fire can also be disorienting; when firing upon a Battle Rifle user or a Sniper Rifle user, the scope will become unusable once the user is hit, reducing their accuracy and giving you the advantage and the incentive to charge assuming you are positioned close enough to your opponent.

Since it has a larger magazine than the MA5C Assault Rifle, you will have to reload less often than if you were to use the MA5C. Because of the large magazine, one can easily continue through targets with little pause for reload. Like other UNSC firearms, the SMG is extremely deadly against unshielded targets, and can kill them rather quickly. In addition, the SMG serves as a better close range secondary weapon when already armed with a Battle Rifle. In combination with the Battle Rifle, the SMG makes a reliable close range support weapon when shotguns and swords are not available. The SMG serves better than the MA5C at close range due to its larger magazine and faster firing-rate, and is an excellent choice of replacement for the Assault Rifle in close combat situations, but not however at medium range. A lot of close-quarter players will wield SMGs in matchmaking to have a rapid, fast-firing weapon, so keep on the move at all times.

The SMG can also form part of the most effective dual-wield combos in the game. The SMG, when dual-wielded with a Plasma Rifle in Halo 3, can be a deadly combination because the Plasma Rifle depletes the opponents shields and the SMG's Armor piercing rounds do the rest. Another favored combo is dual-wielding the SMG with the Plasma Pistol Often referred to as the "noob combo." The charged shot from the Plasma Pistol will deplete the shield of your opponent and a full burst of SMG fire to tear through now-exposed flesh and armor. In Halo 3, the SMG has been improved. By itself, the SMG can be an extremely devastating weapon in close-quarters combat, simply because of its high ammo capacity and lightning fast melee.

Disadvantages
The SMG has 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 ranges the SMG is very powerful and is only outperformed by the Shotgun, Energy Sword and 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 you dual-wield it. This forces you to continually move your reticule down to keep the enemy in your 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 SMG's but gives the advantage of approximately 40+ seconds of non-stop firing.

Influence
The M7 appears to take its design from three real-world firearms. The first is the Heckler and Koch G11, a caseless prototype assault rifle developed in the 1980's. The second is the Fabrique Nationale de Herstal P90. The last one is the HK MP7. The M7 takes its caseless ammunition concept and feed mechanism from the G11, and its design from the latter two. As the MP7 and P90 are both personal defense weapons, it can be assumed that the M7 falls under this classification as well. Its slanted front, foregrip, collapsible stock, and possibly name come from the MP7, while its ergonomic grip and the horizontal magazine configuration come from the P90.

The overall design of the M7 appears similar to the 1984-1990 9x19mm Goncz GA-9 High Tech auto-pistol that was seen in the film Total Recall (1990).

Campaign

 * The M7 SMG is always a devastating weapon when dual-wielded against Elites and Brutes.
 * A Plasma Pistol and a M7 SMG make a great combo against shielded targets.
 * When using dual M7s against Covenant forces be sure to continually strafe; the M7s' particle effect can disorient a player while under fire.
 * Short controlled bursts with a single SMG is required to maintain ammo and effective range when engaging Covenant forces.

Multiplayer

 * The M7 in Halo 2 is not a sound tactical weapon to start off with, but if no other option is available, minimize being killed by staying in a safe zone until a better weapon becomes available.
 * If stuck with an M7, stay in close quarters, and do not venture out where an enemy player has the option of taking you down with longer range weapons.
 * While dual-wielding a M7 and an M6C might sound tactically useful, a player should not consider it unless comfortable with it. The mixing of a full auto and a semi-auto weapon can be confusing and the chances of mistakes are greater.
 * The M7 in Halo 3 is far more effective then its Halo 2 counterpart, and makes a great combo when paired with the BR55HB SR Battle Rifle
 * Dual-Wielding the M7 with either the Plasma Rifle or the Spiker is a favorite combo among skilled players. To maximize the lethality, try firing the Plasma Rifle first following up with a short burst from the M7 to ensure no ammo is wasted.
 * The M7 is a good choice as an anti-air weapon because of the sheer volume of fire being produced if dual-wielded. If facing a banshee it is recommended to let it go into a strafing run on you, and then at medium range open fire. This can kill a banshee very easily. It is unknown if this tactic works on Hornets. The recoil, however, although making the reticule rise and making it seem easier to hit air targets, is not effective in this strategy as the Banshee will likely be flying towards you, and thus move down your screen (if you don't change the camera angle). The recoil however, can be tactically useful for targets flying overhead.
 * The M7 when dual-wielded with the M6C or M6G pistol creates a deadly combo that can take out targets quick and efficiently. However, it requires some skill in order to master it for medium range.

Changes from Halo 2 to Halo 3

 * Red dots at the receiver end of the magazine.
 * Slightly shorter foregrip.
 * Increased accuracy, range, damage and rate of fire.
 * There is now a delay before the barrel actually starts to climb.
 * The sound of the weapon firing is slightly different.
 * Much less common to spawn in both campaign and multiplayer.
 * Handle is more curved, less rectangular.
 * Other various minor cosmetic changes.

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.”

Trivia

 * A silenced SMG, with a smart-linked scope, is the default weapon for Halo 3: ODST ' s new protagonist, The Rookie. It also features a laser sight.
 * The SMG is, in many ways, the same as an MA5B Assault Rifle, as it has relatively similar range, power and capabilities. As with the MA5B, pulsing is a usable technique to increase accuracy and power. This may explain why it is a very common weapon in Halo 2, as the Assault Rifle was in Halo: Combat Evolved. It might also be more popular with Marines than the MA5B, as it is more compact, allowing for closer action, and dual-wieldable, doubling its already considerable power.
 * In Halo 2 when wielding one SMG, the stock is extended, and while dual-wielding the stocks are collapsed. In Halo 3, the stock is always in one position in 3rd person view but collapsed in 1st person when dual wielding, but is still adjustable canonically.
 * Spare ammunition packs for the M7 SMG in Halo 2 are marked in red- the same as the MA5B Assault Rifle.
 * Although the M7 Submachine Gun is primarily issued to vehicle crews, it is also a favorite of commando teams in its sound suppressed version, the M7S. The issuing of the M7 to vehicle crews is similar to how real world vehicle crews are issued carbines and SMGs because of the fact that these weapons would take up less space in a vehicle.
 * While encountered throughout the campaign mode in Halo 2, M7's are only usable in the levels Crow's Nest, Floodgate, Cortana, and Halo in Halo 3.
 * Reloading while dual wielding actually has only the animation of moving your arms down. This is most easily seen in multiplayer.
 * In Halo Wars, the Spartans in the cutscenes are using M7 SMGs that eject empty shell casings, despite the fact that the M7 fires caseless rounds. Also, in the Halo Legends episode "The Babysitter", the M7S can be seen ejecting shell casings. This means that there could be an older version of the M7 that uses traditional cartridges. though it is more likely that these occurrences are just a canon mistake.
 * The M7 submachine gun does about 2/3rds as much damage as the MA5C Assault Rifle. On Heroic difficulty, it takes 24 assault rifle shots to kill a human Marine, compared to about 36 submachine gun shots.
 * Despite remarks made by the Marines that only Spartans can dual-wield the M7, Miranda Keyes was seen dual-wielding it in Halo 2.