When Heckler & Koch introduced the USP in 1993, it marked the first time HK chose to incorporate many traditional handgun design elements in one of its pistols. The HK P7 with its unique cocking mechanism and gas system, the precise roller locked bolt of the P9S, and even the simple, double action only VP70Z all qualify as innovative, on-the-edge designs. So when HK crossed into the mainstream with the USP, two principles guided its development - the first being the use of advanced materials and engineering technology, the second being the creation of a "pistol paradigm", that is a pistol better than all those existing now or in the past. So it should come as no surprise that Heckler & Koch should look to a number of the successful pistols of the past and the present for inspiration in developing the HK USP. John Browning's design for the Government Model is one of the most successful pistols ever produced. Its advantages are well known - reliability, accuracy, dependable stopping power. Many pistols claim these virtues but few combine them as well as the Model 1911. American input during the design phase of the USP was considerable. The controls and many of the pistol's features were directly influenced by American favorites like the Model 1911. And like the Model 1911, the USP can be safely carried "cocked and locked". The USP control lever, a combination safety and decocking lever, is frame mounted and quickly accessible unlike the slide mounted safeties common on many pistols. The control lever has positive stops and returns to the "fire" position after decocking. The control lever functions can be modified by a certified HK armorer; making one pistol easily "convertible" into any of the nine different USP variants. Using a modified Browning-type action with a special patented HK recoil reduction system, the USP is built to take the punishment of the most powerful +P loads. The HK USP is currently available in three calibers: .40 Smith & Wesson, 9mm Parabellum, and most recently added, .45 ACP. The USP .45 was developed in the shadow of HK's work on the Special Operations Pistol (known officially as the MK 23, MOD 0), the.45 ACP handgun designed by Heckler & Koch for the US Special Operations Command. The frame and slide of the USP .45 are slightly larger than those found on the USP40 and USP9, demonstrating its close kinship to the special operations gun. The polymer frame of the USP was designed using technical experience gained by HK engineers in the development of the world's first composite material pistols. An almost identical high-strength/corrosion-free material is used in the .45 ACP Special Operations Pistol. Both the USP and the Special Operations Pistol make extensive use of high-strength polymers and both pistols evolved out of the same desion philosophy - to create a technologically superior handgun. It is worth noting that work on the USP began well before the US Government issued its requirement for the Special Operations Pistol. Nevertheless, design, engineering, and testing overlapped and both programs continue to influence each other. Major metal components on both the USP and Special Operations Pistol are also corrosion resistant. Outside metal surfaces like the one-piece machined steel slide are protected by an extremely hard, nitro-gas carburized black oxide finish. Interal metal parts, including springs, are coated with a special Dow Corning anticorrosion process that reduces friction and wear. Choice of Nine Different Control Arrangements By using a modular approach to the internal components, the control functions of the HK USP can be switched from the left to the right side of the pistol for left handed shooters. The USP can also be converted from one type of trigger/firing mode to another. This includes combination double-action and single-action (DA/SA) modes and double action only modes. This gives a shooter the widest choice of control arrangements. The USP can be modified into virtually any firing mode imaginable. Currently, the USP is available in nine different trigger/firing mode configurations. Variants I and 2 allow the user to carry the pistol in a single-action mode (cocked and locked) with the manual safety engaged. This same pistol, without modification, can be carried in double-action mode, with or without the manual safety engaged. Variants 3 and 4 provide the user with a frame-mounted decocking lever that does not have the "safe" position. This combination only allows the hammer to be lowered from SA position to DA position. It does not provide the "safe" position to prevent the pistol from firing when the trigger is pulled. For the double action only user, variants 5, 6, and 7 of the USP operate as double action only pistols with a bobbed hammer always returning to the DA position (forward) after each shot is fired. To fire each shot, the trigger must be pulled through the smooth DA trigger pull. Variants 5 and 6 have a manual safety lever. No control lever is provided on variant 7. Variants 9 and 10 allow the shooter to carry the pistol in a single-action mode (cocked and locked) with the manual safety engaged. This same pistol, without modification, can be carried in double-action mode (hammer down), with or without the manual safety engaged. The single action mode offers a second strike/double action capability in case of a misfire. The control lever has no decocking function on variants 9 and 10. In addition to a wide selection of trigger/firing modes, the USP has an ambidextrous magazine release lever that is shielded by the trigger guard from inadvertent actuation. The rear of the USP grip is stepped, and combined with the tapered magazine well, makes magazine changes fast and precise. Finger recesses in the grip frame also aid in magazine removal. On 9mm and.40 caliber USPs, magazines are constructed of an extremely tough stainless steel reinforced polymer. Magazines on the USP.45 are all metal. All USP magazines will drop free of the pistol frame when the magazine release is actuated. Also, the HK USP does not have a magazine lockout feature. You can still fire a chambered round even with the magazine removed. An extended slide release lever is positioned to allow easy operation without changing the grip of the shooting hand. Less Felt Recoil With the USP Recoil Reduction System One of the most important unique design features of the HK USP is the mechanical recoil reduction system. This system is incorporated into the recoil/buffer spring assembly located below the barrel. Designed primarily to buffer the slide and barrel and reduce recoil effects on the pistol components, the system also lowers the recoil forces felt by the shooter. The USP recoil reduction system is insensitive to ammunition types and requires no special adjustment or maintenance. It functions effectively in all USP models. Using this same recoil reduction system, one of the HK.45 ACP Special Operations Pistols fired more than 30,000 +P cartridges and 6,000 proof loads without damage to any major components. Abuse and function testing of USP's have seen more than 24,000 rounds fired without a component failure. In fact, this design testing and production evaluation mania of Heckler & Koch engineers is legendary. The HK USP is one of the most thoroughly tested and perfected pistols ever introduced by Heckler & Koch. When the initial design process began more than six years ago, HK engineers already had a large reserve of technical knowledge to draw from. HK Has Wide Experience with Polymers Heckler & Koch pioneered the use of high strength polymers with the P9S and the VP70Z, two pistols designed in the late 1960s. These designs, as well as extensive use of synthetics on HK military rifles and submacbine guns, demonstrated the "promise of plastics" in durability and cost-effective manufacturing. And while all-steel P7 series pistols were the principle handgun product of Heckler & Koch throughout the 1980s, HK's continued interest in polymer technology was evident in several prototype firearms developed during this period. When development work on the USP began in 1990, HK experimented with several polymer compounds. But only one, an advanced injection molded polyamide, met the standards of the HK design team. Injection molded polyamides are super industrial-strength plastics known for their resistance to high temperatures, wear, chemicals, and radiation. They are lighter than steel, corrosion resistant, and have a higher tensile strength than aluminum. Reinforced with microscopic glass fibers, the USP polyamide is dimensionally more stable than many polymers used by other manufacturers. Dimensional stability is an important factor to ensure pins and other critical parts are held securely. The frame of the USP is also steel reinforced to provide additional strength and aid in giving the pistol a proper weight and balance. Tough Military Standards Used in USP Tests The testing process of the USP, already extreme, exceeded strict NATO AC-225 Military Specification Standards and in many ways mirrors the regimen the HK Special Operations Pistol was subjected to by US Government testers. The barrel of the USP is cold-hammer forged from a high-grade chromium steel - the same type of steel used in cannon barrels. For increased velocity and longer barrel life, all USP barrels now have a polygonal profile. During testing, a bullet was deliberately lodged in a USP barrel. Another cartridge was then fired into the obstructing bullet. The second bullet cleared the barrel, resulting in a barely noticeable bulge. The pistol was then fired for accuracy and the resulting group measured less than 2 1/2 inches at 25 meters. Other less destructive tests reveal much about USP reliability and durability. Function testing a wide selection of ammunition types, one test gun fired more than 10,000 rounds without a single malfunction. That means no stovepipes, no failures to feed or eject; no jams! Endurance firing of test samples has passed 24,000 rounds of high performance .40 S&W ammunition without any parts failures. Severe temperature tests required the USP be frozen at -44°F (-42°C) and then fired, frozen again, quickly heated to 153 F° (67°C), and then fired again. These temperature spectrum tests were continually repeated with no adverse effects on the USP. Demanding NATO Mil-Spec mud and rain tests were conducted, again with the USP passing without difficulty. Water immersion and salt spray also presented no problems to the USP. Outside metal surfaces of the USP are covered with an extremely hard nitro-gas carburized and black oxidized finish. Interal metal parts are coated with a special Dow-Corning© process that reduces friction and wear. Both the intemal and exteral finishes have proved to be especially corrosion resistant. For more than two years, German Navy combat divers have used the same process on weapons parts without any signs of rust or corrosion. Safety testing exceeded the ANSI/SAAMI requirements adopted in May 1990. These included dropping a USP with a primed cartridge and decocked hammer on a variety of hard surfaces without discharging. The USP easily surpassed these commercial requirements, as well as tough German Army and police tests including repeated drop tests from six feet, hammer first, onto a steel backed concrete slab. Proof round firing resulted in no cracks, deformations, or increase in head space. Attempts to fire the USP pistol with an unlocked breech proved impossible. HK firearms are known worldwide for their accuracy. Testing with a variety of ammunition proved the USP meets these high standards. The HK patented recoil reduction system, a mechanical dual spring buffering device, is another feature common to the USP and the HK Special Operations Pistol. During the USP testing phase, HK engineers discovered this innovative unit reduces the peak force acting on the USP grip to less than 300 Newtons (66 pounds). Peak force shock on competing .40 caliber polymer and metal framed pistols climbed to more than 5000 Newtons (1,102 pounds). The primary benefit of low peak shock is a decrease in wear and tear on pistol components, a great concern with the powerful +P cartridge in 9mm, 40 S&W. and.45 ACP. Reduction of peak shock forces also contributes to softer recoil for the shooter, although these "felt recoil" values are much more subjective. Even after the commercial introduction of the USP in 1993, testing and product improvement have continued. USP test pistols have already fired more than 24,000 rounds of.40 caliber ammunition without any component failures. Heckler & Koch engineers are set to surpass the standard set by the HK Special Operations Pistol of 30,000 rounds. The USP project demonstrates a simple, guiding principle of Heckler & Koch engineering; form follows function. All HK pistols are designed and manufactured to meet the operational requirements of the most demanding users.