No, it's not "yet another MP5 variant". The UMP Universal Machine Pistol is totally separate from its better-known little brother, and it's chambered in .45ACP.
Here I paste the manufacturer's specifications:
"The UMP is a cost-effective, state-of-the-art submachine gun that offers users the advantages of light weight, low initial purchase and maintenance costs, uncompromising reliability, and precision accuracy with low felt recoil.
The UMP is available in .45 ACP and .40 S&W variants.
The UMP45 provides the user with a magazine capacity of 25 rounds* with an accurate range of 100 yards or more, well beyond that of any issue handgun or shotgun. Due to its small size (less than 18 inches with the buttstock folded) and 41/2 pound unloaded weight, the UMP is the perfect choice for use in or around vehicles. Its size and low weight also make it the ideal weapon for smaller stature officers who have difficulty handling the size, weight, and excessive felt recoil of a full size rifle or shotgun.
The UMP45 is designed and tested to fire all types of .45 ACP ammunition—including subsonic and supersonic loads, cartridges assembled with ball, high performance hollowpoint projectiles, and even enhanced velocity +P offerings. The UMP45 also fires nontoxic and frangible training ammunition without modification.
For familiarity of training, the UMP offers fully ambidextrous operating controls and sling attachment points similar to those found on other HK rifles and submachine guns. A convenient bolt catch holds the bolt open when the last round is fired and along with the flared magazine well makes for quick and easy reloads.
Hard points molded into the polymer receiver of the weapon allow for the attachment of a wide assortment of optional mounting rails and accessories, such as assault sights, tactical lights, and vertical foregrips.
Additional standard features include fully adjustable iron sights with a dual flip-up rear aperture, an HK multipurpose tactical carrying sling, and a detachable vertical handstop. Optional tritium sights are also available.
UMP firing mode choices include semiautomatic only, semiautomatic and 2-round burst, or semiautomatic and fully automatic modes of fire.
With the exception of the barrel, bolt, and certain internal component parts, the UMP45 is constructed entirely from tough, lightweight glass-fiber reinforced polymer. The UMP magazines, also made of high strength polymer, feature a transparent ammunition-viewing strip that allows the user to see the type and quantity of ammunition inside.
The sturdy UMP folding buttstock has a rubber cheek piece and buttpad and reduces the overall length of the weapon by nearly ten inches when closed.
Like all HK submachine guns, the UMP fires from the closed bolt position to improve accuracy and enhance safety when handling the weapon. A passive internal firing pin block within the bolt prevents the weapon from firing if dropped.
Disassembly of the UMP is easy. The weapon fieldstrips into three basic assembly groups with the removal of a single locking pin, making cleaning and maintenance fast and simple.
No other submachine gun in the world offers the speed and simplicity of the unique HK Quick Connect sound suppressor attachment interface found on the muzzle of the UMP. The sound suppressor can be installed and removed easily in seconds.
For tactical team use as the ultimate CQB weapon, for issue as a squad car carbine, for a pistol caliber companion weapon to HK’s new .223 G36 rifle or carbine, or as a pistol caliber long gun to supplement HK .45 or .40 caliber handguns—the UMP is the world’s most advanced submachine gun for the uncompromising user. For the new millennium, the UMP reigns supreme."
Here I paste the manufacturer's specifications:
"The UMP is a cost-effective, state-of-the-art submachine gun that offers users the advantages of light weight, low initial purchase and maintenance costs, uncompromising reliability, and precision accuracy with low felt recoil.
The UMP is available in .45 ACP and .40 S&W variants.
The UMP45 provides the user with a magazine capacity of 25 rounds* with an accurate range of 100 yards or more, well beyond that of any issue handgun or shotgun. Due to its small size (less than 18 inches with the buttstock folded) and 41/2 pound unloaded weight, the UMP is the perfect choice for use in or around vehicles. Its size and low weight also make it the ideal weapon for smaller stature officers who have difficulty handling the size, weight, and excessive felt recoil of a full size rifle or shotgun.
The UMP45 is designed and tested to fire all types of .45 ACP ammunition—including subsonic and supersonic loads, cartridges assembled with ball, high performance hollowpoint projectiles, and even enhanced velocity +P offerings. The UMP45 also fires nontoxic and frangible training ammunition without modification.
For familiarity of training, the UMP offers fully ambidextrous operating controls and sling attachment points similar to those found on other HK rifles and submachine guns. A convenient bolt catch holds the bolt open when the last round is fired and along with the flared magazine well makes for quick and easy reloads.
Hard points molded into the polymer receiver of the weapon allow for the attachment of a wide assortment of optional mounting rails and accessories, such as assault sights, tactical lights, and vertical foregrips.
Additional standard features include fully adjustable iron sights with a dual flip-up rear aperture, an HK multipurpose tactical carrying sling, and a detachable vertical handstop. Optional tritium sights are also available.
UMP firing mode choices include semiautomatic only, semiautomatic and 2-round burst, or semiautomatic and fully automatic modes of fire.
With the exception of the barrel, bolt, and certain internal component parts, the UMP45 is constructed entirely from tough, lightweight glass-fiber reinforced polymer. The UMP magazines, also made of high strength polymer, feature a transparent ammunition-viewing strip that allows the user to see the type and quantity of ammunition inside.
The sturdy UMP folding buttstock has a rubber cheek piece and buttpad and reduces the overall length of the weapon by nearly ten inches when closed.
Like all HK submachine guns, the UMP fires from the closed bolt position to improve accuracy and enhance safety when handling the weapon. A passive internal firing pin block within the bolt prevents the weapon from firing if dropped.
Disassembly of the UMP is easy. The weapon fieldstrips into three basic assembly groups with the removal of a single locking pin, making cleaning and maintenance fast and simple.
No other submachine gun in the world offers the speed and simplicity of the unique HK Quick Connect sound suppressor attachment interface found on the muzzle of the UMP. The sound suppressor can be installed and removed easily in seconds.
For tactical team use as the ultimate CQB weapon, for issue as a squad car carbine, for a pistol caliber companion weapon to HK’s new .223 G36 rifle or carbine, or as a pistol caliber long gun to supplement HK .45 or .40 caliber handguns—the UMP is the world’s most advanced submachine gun for the uncompromising user. For the new millennium, the UMP reigns supreme."