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
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
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