History

The MP7 is a German submachine gun manufactured by Heckler & Koch (H&K) and chambered for the 4.6x30mm cartridge. It was designed with the new cartridge to meet NATO requirements published in 1989, as these requirements call for a personal defense weapon (PDW) class firearm, with a greater ability to defeat body armor than current weapons limited to conventional pistol cartridges. The MP7 went into production in 2001. It is a direct rival to the FN P90, also developed in response to NATO's requirement. The weapon has been revised since its introduction and the current production version is the MP7A1.
The proliferation of high-quality body armor has begun to make guns that fire pistol ammunition (such as HK's earlier MP5 submachine gun or USP pistol) ineffective. In response to this trend, HK designed the MP7 (along with the now cancelled UCP pistol, which uses the same ammunition) to penetrate body armor, but small enough to be used in place of either a pistol or a submachine gun.

The MP7 essentially operates like a scaled-down assault rifle, with the same action as HK's G36, a short stroke piston. It fires a specially designed, armor-piercing round with a muzzle velocity nearly as high as that of the 5.56x45mm NATO cartridge used by many modern rifles. This ammunition is unique among submachine guns in that the bullet is made almost entirely of a hardened steel penetrator instead of softer copper or lead. The ammunition is virtually exclusive to the gun (save for the now cancelled H&K UCP and a planned variant of the Brügger & Thomet MP9) and also offers low recoil. VBR of Belgium produces a 4.6x30mm 2-part controlled fragmenting projectile that is claimed to increase the content of the permanent wound cavity and double the chance to hit a vital organ. Heckler & Koch claims that the CPS Black Tip ammunition made by Fiocchi has a muzzle energy of approximately 525 J, which would be comparable to 9x19mm Parabellum rounds.
 
The round also has a small diameter (it can almost be described as a scaled down .223 Remington), allowing for high capacity in a very small magazine. The weapon allows a conventional 20-round, 30-round, or 40-round box magazine to be fit within the pistol grip (the 20-round magazine being comparable in size to a 15-round 9 mm magazine, while the 40-round magazine compares to a 30-round 9 mm magazine). The weapon features an ambidextrous fire-select lever and rear cocking grip. It has an extendable stock and a folding front grip; it can be fired either one-handed or two-handed. It is compact and light, due to the use of polymers in its construction.

Singleplayer/Spec-Ops

Multiplayer

The MP7 is unlocked at level 74 in Call of Duty: Modern Warfare 3 multiplayer. The MP7 is an excellent "all purpose" weapon due to it being good in every category, as opposed to most SMGs that are great in some and terrible in another for balance. The MP7 features the second highest magazine capacity of 40 rounds, second only to the P90's 50 round magazine, and has a moderately high rate of fire as well as moderate power and controllable recoil. All these features together allow the MP7 to be a reliable close combat spraying weapon, as well as an effective long range weapon when needed. The MP7's iron sights are very clear, limiting the need for an optic, though its idle sway can certainly throw off the player's aim. As such, the proficiencies Stability or Range are recommended to either reduce sway or to make the shots that do connect more effective.

Attachments

Attachments	Challenges	Icon
Reflex Sight	Get 60 kills while looking through a Red Dot Sight attached to a SMG.
Silencer	Get 60 kills with a Silencer attached to a SMG.
Rapid Fire	Get 30 kills with Rapid Fire attached to a SMG.
ACOG Scope	Get 20 kills while looking through a ACOG Scope attached to a SMG.
HAMR	Get 40 kills with a HAMR Scope attached to a SMG.
Holographic Sight	Get 20 kills while looking through a Holographic Sight attached to a SMG.
Extended Mags	Get 40 kills with Extended Mags attached to a SMG.
Thermal	Get 40 kills while looking through a Thermal attached to a SMG.

Proficiencies

Proficiency	Description	Icon
Kick	Kick Reduces recoil by 20%, allowing for steadier full-auto and faster recovery from shots.
Range	Offers a 25% boosted effective range. This is very useful on Shotguns, particularly the automatic variants. Some SMGs can benefit from this upgrade, as well, especially if you are intent on using medium-range optics.
Attachment	Allows the use of 2 Attachments. It is a solid all-around Proficiency, useful in many situations. This Proficiency is also notably useful for stealth builds, as it allows you to use a Silencer alongside any other Attachment. The Attachment Proficiency is also helpful if you are still getting comfortable with iron sights, as it allows you to take and optical Attachment and a second utility Attachment.
Focus	Reduces visual recoil by 50% when you are hit. Focus is very effective for SMGs and Shotguns. It is also helpful for ARs, as it can keep your shots on target when you enter a heads-up one-on-one firefight.
Melee	Grants 35% faster melee recovery. Melee can be useful if you are stalking targets with a stealth Shotgun build. With the Riot Shield, it allows you to take down targets much more quickly at close range
Stability	Reduces idle sway by 25%. Consider this to be an 'automatic' Breath for long-range combat. It is most useful on LMGs, as they need the enhanced accuracy for long-range shots, though ARs also benefit from it.

Challenges