USP

The USP is the third free pistol in the game and is the 110th gun available in "Gun Type".

Introduction
The USP [Universale Selbstladepistole or "universal self-loading pistol"] is a semi-automatic pistol developed in Germany by Heckler & Koch GmbH [H&K] of Oberndorf am Neckar as a replacement for the P7 series of handguns.

History
Design work on a new family of pistols commenced in September 1989 focused primarily on the U.S commercial and law enforcement markets. In 1991, USP prototypes participated in rigorous testing alongside H&K's entry in the OHWS [Offensive Handgun Weapon System] program requested by the U.S Special Operatoins Command [USSOCOM] and which would later result in the Mk 23 Mod 0. The USP prototypes were then refined in 1992, based on input from the OHWS trials and the design was finalised in December of the same year. The USP was formally introduced in January 1993 with the USP40 model [the base version] chambered for the increasingly popular .40 S&W cartridge, followed soon by the USP9 [using the 9x19mm Parabellum cartridge] and in May 1995, the USP45 [caliber .45 ACP]

The USP marked the first time H&K chose to incorporate many traditional handgun design elements, such as those of John Browning's M1911, in one pistol. Two priniciples guided its development; the first being the use of a molded polymer frame and the second being the creation of a "pistol paradigm". Heckler & Koch observed the strong points of its previous successful pistols for insight in developing the USP. Previous H&K pistol innovations include the unique squeeze-cocking mechanism of the P7, the precise roller-delayed blowback operation of the P9S, and the plastic frame and double action only trigger system used in the VP70Z. In contrast to these ambitious designs, the USP uses a Browning-style cam-locked action, similar to that developed by John Browning for use in the Hi-power and M1911 pistols.

Design Details
The USP is a semi-automatic pistol with a mechanically locked breech using the short recoil method of operation. This rather conventional lock-up system has a large rectangular lug over the barrel's chamber that rides into and engages the ejection port cut-out in the slide. When a cartridge is fired, pressures generated by the ignited powder drive the cartridge casing back against the breech face on the slide, driving back both the barrel and slide as they remain locked together in the manner described above. After 3mm [0.12 inches] of unrestricted rearward travel, the projectile has left the barrel and gas pressures have dropped to a safe level. A shaped lug on the underside of the barrel chamber comes into contact with a hooked locking block at the end of the steel recoil spring guide rod, lowering the rear end of the barrel and stopping the barrel's rearward movement. The recoil spring assembly is held in place by the slide stop lever's axis pin and a round cut-out at the front of the slide. For enhanced reliability in high-dust environments, the locking surface on the front top of the barrel's locking lug is tapered with a forward slope. This tapered surface produces a camming action which assists in positive lock-up in the presence of heavy fouling and debris. In this way, the USP shares many design features with the M1911 pistol, although apparently updated for easier operation.

On of the most significant of the USP is the mechanical recoil reduction system. This system is incorporated into the recoil spring assembly, located below the barrel and consists of a heavy, captive coil spring around the guide rod. Designed primarily to buffer the slide and barrel reduce recoil effects on the pistol components, the system also lowers the recoil forces felt by the shooter up to 30%. The USP recoil reduction system is insensitive to ammunition types and does note require adjustment or maintenance. It functions effectively in all USP models. Using this same recoil reduction system, one of the related J&K Mk 23 .45 ACP pistols fired more than 30,000 high pressure power cartridges and 6,000 proof loads without damage or excessive wear to any major components. Abuse and function-testing of USPs have seen more than 20,000 rounds of .40 S&W fired without a component failure. Milspec environmental tests were conducted in high and low temperatures, in mud, immersed in water and in salt sprat. In one particular test, a bullet was deliberately lodged in the barrel and another bullet was fired to clear the obstruction. The barrel was successfully cleared with only minor structural deformation and continued to produce consistent groups when test fired for accuracy.

Major metal components on both the USP and Special Operations Pistol are corrosion-resistant. Outside metal surfaces, such as the steel slide are protected by a proprietary "Hostile Environment" nitride finish. Internal metal parts, such as springs, are coated with a Dow Corning anti-corrosion chemical to reduce friction and wear.

The USP is composed of a total of 54 parts and is broken down into 7 major components for maintenance and cleaning: the barrel, slide, recoil spring, recoil spring guide rod, the frame, slide stop and magazine. This is done by retracting the slide back to align the slide stop axis pin with the disassembly notch on the left side of the slide and withdrawing the axis pin.

Variants
The USP was originally built around the .40 S&W cartridge, but a 9x19mm Parabellum was introduced at the same time. In May 1995, Hecklr & Koch introduced a .45 ACP variant. The USP Compact series was introduced in 1996 and is available in 9mm Parabellum, .40 S&W, .45 CAP, and exclusively to the Compact model, .357 SIG. Other variants of the standard USP include the USP Tactical, USP Expert, USP Match, USP Elite and the standard sidearm of the German Armed Forces [Bundeswehr] - the P8.

One of the remarkable features of the USP is the wide variety of the trigger styles available, which may be quickly swapped. There are nine commercially available modifications [called "variants" by HK].

By using a modular approach to the internal components, the control functions of the USP can be switched from the left side 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 of double-actoin and single-action [DA/SA] modes and double-action only [DAO] modes.

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 combines well with the tapered magazine, making magazine changes faster due to lack of user-assisted guiding. Finger recesses in the grip frame also aid in magazine removal. On 9mm and .40 calibre USPs, magazines are constructed of polymer reinforced with stainless steel. Magazines on the USP .45 are all-metal. All USP magazines will drop free of the pistol frame when the magazine release is depressed. Also, the USP does not have a magazine lockout feature [also known as a magazine disconnector]. Thus is is possible to fire a chamberd 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.

Variants 1 and 2 [Double Action/Single Action, Decocking and Safety Lever]
Variants 1 [lever on left] and 2 [lever on right] 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, canbe carried in double-action mode, with or without the manual safety engaged and with the benefit of a decocking lever.

Variants 3 and 4 [Double Action/Single Action, Decocking Lever, But No Safety]
Variants 3 [lever on left] and 4 [lever on right] 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.

Variants 5 and 6 [Double Action Only, With Safety Leve]
For the double action only user, variants 5 [lever on left], 6 [lever on right], and 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.

Variant 7 [Double Action Only, No Control Lever]
No control lever is provided on variant 7.

Variants 9 and 10 [Double Action/Single Action, Safety lever, But No Decocking]
Variants 9 [lever on left] and 10 [lever on right] 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 double 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 so one would have to carefully lower the hammer manually.

LEM [Law Enforcement Modification] Trigger
Developed especially for the U.S government, the Law Enforcement Modification [or LEM for short], is a USP DAO [Double-Action Only] model with a unique trigger mechanism. This mechanism improves the double action trigger performance and reduces the weight of the DAO trigger pull to 7.5-8.5 pounds, uses a stronger hammer spring, and shortens the reset. Aside from the LEM mechanism, it is identical the USP Variant 7 [DAO] model.

USP Custom Sport
Almost identical to the standard USP, the Custom sport is aimed at target - and practical shooting users. The Custom Sport has a match grade barrel, match trigger and adjustable sights.

USP Compact
The first USP Compact models appeared in 1994. These are scaled-down USPs, and are available in all the same cartridges as the full size version, and additionally the .357 SIG. Due to the smaller size of the frame, magazines for the Compact variant may have a handgrip extension to better accommodate the Shooter's hand. Standard flat floorplates are also available for the USP Compact magazines. The USP Compact comes standard with a bobbed hammer equipped with a flat rubber external thumb grip. This reduces possible snag from the hammer on a holster or clothing while the pistol is being drawn, but still allows the USP Compact to be cocked from a decocked position even in the absence of a spurred hammer. This can be done since decocking the weapon does not fully drop the hammer, leaving it in a somewhat "half-cocked" state. However, the USP Compact cannot be cocked from a dry-fired position as the hammer will be flush to the back of the slide, although the operator could pull the trigger approximately halfway back in a dry-fired position to put the hammer in a half-cocked state, allowing the hammer to be fully cocked with the thumb. A spurred hammer, similar to the one that comes standard on the P10 can be installed onto the USP Compact. USP Compact models lack the mechanical recoil reduction system of the larger full sized USP pistols. Instead, a more compact recoil buffering system is composed of a polymer bushing, around the captive recoil spring, which is designed to absorb energy at the end of the slide's travel rearward. This polymer bushing, with a estimated lifespan of around 20,000 rounds, is used instead of the double spring/captive recoil spring/guide rod found in the full sized USP.

In addition to the variants previously described for the full size USP, an ambidextrous safety is available from the manufacturer as a separate part. After installation by a competent gunsmith, the USP Compact effectively becomes a right or left-handed firearm with respect to the decocker and manual safety functions.

Heckler & Koch does not authorise caliber conversions, but a separate barrel for a .357 SIG or .40 S&W can be purchased from HK, or from companies like Midway USA or Jarvis, Inc. EFK Fire Dragon, an Arizona based pistol accessories company produces conversion barrel for both Full Size and Compact USP models. These conversion barrels can convert a .40 S&W to .357 SIG, and vice versa. They also manufacture 9mm conversion barrels. These 9mm conversion barrels can convert a 40/357 SIG to a 9mm, but not a 9mm to a 40/.357 SIG. Also, a more powerful recoil spring may be needed for a .356 SIG conversion as the .357 SIG operates at a higher PSI.