The Heckler & Koch UMP is their next-generation submachine gun. The name UMP derives from the German Universal Machinenpistole, which is an accurate description of the intended role of the UMP: lightweight, low-recoiled and extremely reliable like a pistol, with high accuracy and rate of fire like a machine gun or assault rifle.

Width: 2.5 inches (63.5 mm)
Height: 10.94 inches (277.8 mm)
Length, stock collapsed: 15.75 inches (400 mm)
Length, stock extended: 27.17 inches (600 mm)
Weight: 4.63 pounds (2.10 kg)
Standard Cyclic Rate: 600 rpm
Unit Cost: about $800 USD for law enforcement.

Physical Appearance
Upon first inspection, it is immediately apparent how much the engineers of Heckler & Koch drew upon the MP5 and G36C in the design of the UMP. The first detail that will aid in identification is the folding skeletal stock rather than the typical MP5 collapsing stock. Secondly, the two receiver-piece UMP is largely polycarbonate and polymer in construction. The only metal parts are the parts actually involved in the action of the firing mechanism (which is a straight blowback, traditional firing mechanism for H&K weapons) and the ambidextrous 'navy' trigger group (which can be identified by the safe, single fire, two round burst and full automatic settings). Despite the traditional blowback design (which reduces recoil), the bolt locks open after the last round, as is custom with American firearms. This is a departure from the MP5 series and the G36 series.

The foregrip and barrel design of the UMP is a two piece, vented polymer handgrip similar to the G36C, contrasted to the MP5 one piece metal foregrip. Although a mounting rail (conforming to MILSPEC) is available to allow the operator to use a laser sight or scope, most operators will prefer the "ghost ring" style sights largely because they are easy to use in combat situations with their tritium lighting and because the UMP is not intended to be used as a precision sniper rifle. Finally, the identifying feel characteristic of the UMP is the weight and the balance. Whereas the balance (center of gravity) of the G36 is close to the barrel for better accuracy and the balance of the MP5 is close to the stock for high mobility in close quarters, the UMP is balanced very close to the center of the weapon. In my experience with the UMP, this contributes nicely to the overall low weight of the UMP. The polymer construction makes it feel light- almost like a toy cork gun should feel, which is scary considering that the plastic toy you hold deserves the respect afforded to a lethal weapon.

The UMP is available in three models to chamber three calibers: .45 ACP, .40 S&W, and 9x19mm Parabellum. Each has their relative advantages, however the common denominator is their widespread usage amongst law enforcement units. The UMP accepts the inline magazine ubiquitous to the MP5, allowing the operator to carry 30 rounds in the UMP and UMP40, and 25 rounds in the UMP45. The advantage of the inline magazine is that it can easily be handed from a UMP operator to another operator employing a properly chambered MP5. This is not only a useful design feature, but also good marketing on the part of Heckler & Koch, as the UMP is marketed towards the same organizations that made the MP5 such a remarkable seller. As MP5 units reach the end of their service life expectancy, Heckler & Koch will undoubtably pitch the UMP, touting the ability to change over unit by unit and maintain much of the accessory equipment and maintenance purchased for the older MP5 units. The magazine housing is made of a polycarbonate based reinforced plastic. It has a transparent side panel, allowing the operator to visually inspect the number of rounds remaining without removing the magazine. Advertised cyclic rates are 580 rpm with 230 grain ball, and 700 rpm with 185 grain +P ammunition.

Many of the MP5 accessories are also available for the UMP. The most popular of these accessories is a tri-positional carrying sling that allows the operator to carry the UMP across the chest, vertically on the back or in a braced firing position without readjusting the sling. The use of the sling reduces fatigue in carrying the weapon, while increasing accuracy when the weapon is employed. A Bruegger & Thomet suppressor (not to be confused with a silencer) is available. This makes use of a quick connect attachment rather than the MP5 three-bolt attachment. Use of the suppressor reduces muzzle flash and blast, however, it also results in a slight decrease in projectile velocity and accuracy. Various posture accessories such as hand stops, the Surefire M900 Vertical Foregrip (for extreme CQB), and integrated hand rails are also available for users of similar weapons such as the Steyr TMP and Heckler & Koch G36 who want to maintain non-standard postures from their old weapons. SureFire forearm mounted flashlights have been made available and are employed throughout the world as well.

elem_125 says It should also be noted though that the UMP (aka the peacemaker) is being aimed at combat support units, who are behind the front lines, but still need to be able to defend themselves if needed. also, when chambered with 9x19 parabellum, a round from the UMP can penetrate up to 20 layers of kevlar.