M7 Caseless Submachine Gun

The M7/Caseless Sub Machine Gun, colloquially termed the Submachine Gun by UNSC personnel and the SMG by Halo players, is a widely used United Nations Space Command firearm. Having been in use at least since 2531, the M7 SMG has proven its effectiveness time and again in combat. There is a suppressor that can be mounted to the gun for stealth missions. (Ghosts of Onyx, page 32 and First Strike,page 300)

Advantages
The SMG's strength is its high rate of fire. While individual shots are not enormously damaging, its full automatic mode of fire has led to it being dubbed the "Bullet Hose" by users in the UNSC. When dual-wielding, it allows the users to engulf the targets in a veritable torrent of projectiles. The weapon's accuracy can also be significantly increased by firing it in short, controlled bursts. In the hands of an experienced player, the SMG is exceptionally useful for suppressing snipers at medium range ( one direct hit can knock a sniper out of his scope) in Halo 2's multiplayer. Ammunition is also very plentiful.

Disadvantages
The SMG has a number of shortcomings. Its accuracy when fired continuously is strictly limited unless used at close range (although this can be remedied somewhat through burst fire). Furthermore, full automatic fire leads to enormous recoil, forcing the SMG's muzzle steadily upward. You will need to compensate for this effect by constantly adjusting your aim. Finally, its phenomenal capacity for filling the air with lead means that its magazine can be depleted in what will seem like a heartbeat.

Multiplayer Tactics
The SMG is the most commonly used and found weapon early in the game. Most games start off with someone wielding this weapon. Therefore, its the easiest weapon to find among the dead.

SMG + Plasma Rifle
SMG + Plasma Rifle is among the best and most flexible dual wielding combinations. This combination is best used to fight off many opponents in one setting. It also gives you the flexibility of using two weapons at once while simultaneously destroying the opponents shield and health. Remember to reload the SMG and make sure the Plasma Rifle does not overheat.

SMG + Plasma Pistol
This combination is best at dealing with singular opponents. Be careful of the lapse between the Plasma Pistol recharge and the reload of the SMG. It is difficult to kill someone and then engage someone else right after. This is a very commonly used combo in small maps such as Lockout and Beaver Creek. Also, be wary the the Plasma Pistol's limited ammunition: only ten overcharged shots may be used before the pistol must be replaced.

SMG + SMG
Probably the easiest combination to hang onto until you find a plasma rifle. This combination is the most predominant in the level Foundation, where there are no Plasma Rifles and SMGs are easy to find among dead bodies and elsewhere on the map. This combination, however, is difficult to use in other places because of the problems of draining enemy shields. If you are using two SMGs against a SMG + Plasma Rifle Combo head on, you must be careful with your strafing pattern in order to avoid the plasma rifle's shots. Otherwise, you will lose. Also be aware that the recoil effect of the SMG is increased with this combo. Though not technically inferior to the SMG + Plasma Rifle Combo in all instances, the SMG + SMG Combo is usually less desired by most players because of the more demanding nature of the skills needed to use it properly.

SMG + Needler
Not very useful. Easy to pick up in Burial Mounds (Level) and Beaver Creek (Level) where the Needler is close. The most important, and sad attribute to the Needler is a losing advantage. It has been found that if this is your only solution, you've become Black in a chess game. You can only kill the person that has just stepped over you when they're pumped full of needler ammo, or die quickly, only denting their shields. The latter usually happens with a more experienced, strafing opponent. In this case it would probably be better to not pick up the Needler and just stick with a single SMG because you'll at least be able to use grenades and melee without dropping a weapon.

SMG + Magnum
This can be the worst combination, or even better than dual SMGs, depending on your skill. If you are able to properly use the SMG and consistently perform headshots with the magnum, you will be very successful with this combination. Practice makes perfect.

Appearances
The SMG is a weapon that was introduced in Halo 2 as one of the foundational weapons for the new dual wielding system. It shares it's aiming reticle and ammo count with the MA5B Assault Rifle from Halo 1 (as well as serving the same basic function in the UNSC arsenal).

The weapon will return in Halo 3. The SMG in Halo 3 appears to look the same as the Halo 2 version. How it handles and fires is to be determined. EGM has said it will shoot faster, and that it is now pointier.