The Universale Selbstladepistole (USP), or "Universal Self-Loading Pistol," is a commercially successful semi-automatic handgun that has been produced by the German firearms manufacturer Heckler & Koch since 1993. It is currently used by civilians, law enforcement officers and soldiers all over the world for both self-defense and sport, and is regarded by many as the most resilient and versatile weapon of its sort ever made.
Important Details and Numbers:
The Heckler & Koch USP has a number of configurations (Compact, Elite, Expert, Match, and Tactical), all of which have different dimensions and features. However, suffice it to say that the USP is a medium-sized pistol with an unloaded weight between 1.5 and 2.4 pounds, and a barrel ranging in length from 3.5 to six inches. It is typically chambered to operate on 9mm Luger Parabellum, .357 SIG, .40 S&W or .45 ACP ammunition, boasting four active and passive safety mechanisms, a magazine with a capacity of as many as 15 rounds, and an extremely effective mechanical recoil reduction system -- reducing the kickback on the gun by as much as 1500%.
One of the USP's most important features is that it is specifically designed to allow for the decocking mechanism, safety lever and action functionality (single- or double-) to be removed or replaced with relative ease, allowing for nine possible variants of any USP configuration. Handedness is not an issue with the USP; if you are left-handed, the safety and decocking levers can just be switched to the other side a right-hand-operable gun. And if you are frightened by the possibility of inadvertently chambering a round after unloading a clip, you can have the single-action feature of you gun changed to DAO (double-action only).
Durability Testing:
The Heckler & Koch USP is renowned for being a very durable gun. It has a polymer shell, and a barrel cold-forged from chromium steel -- the same stuff used for the barrels of high-caliber cannons. All of the other metal components of the gun are nitrogen-treated steel, which is both incredibly strong and stainless.
It has been said that the USP is the most rigorously tested firearm in history. It was tested to exceed NATO AC-225 Military Specification Standards, easily clearing standard testing methods and demanding more physical challenge. In one test by the German Bundeswehr, the USP was cooled to -42 Celsius, fired, cooled again, heated to 67 Celsius, and fired again. It always operated as expected, without any measurable performance failure. In another test, a bullet was intentionally lodged in the USP's barrel, and another was fired into it. Both bullets cleared the barrel, leaving only "a barely noticeable bulge". The gun was then tested for accuracy at a distance of 25 meters. The resultant group had a spread of only 2.5 inches.
The USP has also been tested for corrosion resistance. With routine cleanings, its performance is entirely unaffected by frequent exposure to moisture and salt water, including submersion (although obviously ammunition might be another story altogether). This resistance is extraordinary; only the Glock 17 is known to be so weather-proofed.
References:
http://en.wikipedia.org/wiki/Heckler_&_Koch_USP
http://www.streetpro.com/usp/uspintro.html
http://www.streetpro.com/usp/torture.html