History

The UMP (Universale Maschinenpistole, German for "Universal Machine Pistol") is a submachine gun developed and manufactured by Heckler & Koch. The UMP has been adopted by various agencies such as the U.S. Customs and Border Protection. Heckler & Koch developed the UMP as a successor to the MP5, though both remain in production.

The UMP is a blowback-operated, magazine-fed submachine gun firing from a closed bolt. As originally designed, the UMP is chambered for larger cartridges than other submachine guns like the MP5, to provide more stopping power against unarmored targets (with a slightly lower effective range) than the 9x19mm MP5 provides. A larger cartridge produces more recoil, and makes control more difficult in fully automatic firing. To mitigate this, the cyclic rate of fire was reduced to 650 rounds/min (600 rounds/min for the UMP45), which makes it one of the slower firing submachine guns on the market.
 
The UMP9 (the 9x19mm version of the UMP) is almost 0.45 kg (almost 1 lb) lighter than its MP5 counterpart. Its predominantly polymer construction reduces both its weight and the number of parts susceptible to corrosion.
 
The UMP is available in four trigger group configurations, featuring different combinations of semi-automatic, 2-round burst, fully automatic, and safe settings. It features a side-folding buttstock to reduce its length during transport. When the last round of the UMP is fired, the bolt locks open, and can be released via a catch on the left side. The standard viewing sights comprise an aperture rear sight and a front ring with a vertical post. It can mount four Picatinny rails (one on top of the receiver, and one on the right, left, and the bottom of the handguard) for the attachment of accessories such as optical sights, flashlights, or laser sights. Vertical foregrips can be attached to the bottom rail for increased controllability during burst and automatic fire.

Singleplayer/Spec-Ops

The UMP45 is available from the Weapons Armory after being unlocked at level 4. It costs $2000. 

Multiplayer

The UMP45 appears in Modern Warfare 3's multiplayer. It is available in one of the five default classes. The UMP45 has much lower damage at range, unlike its Modern Warfare 2 counterpart. It does, however, have a slightly faster fire rate, and features the high penetration of LMGs and Sniper Rifles, making it ideal for close quarters combat and room clearing.

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