.40 S&W
.40 S&W (third from right) compared to other cartridges.
Type	Pistol
Place of origin	United States
Production history
Designer	Smith & Wesson
Designed	January 17, 1990
Produced	1990–Present
Specifications
Parent case	10mm Auto
Case type	Rimless, Straight
Bullet diameter	.400 in (10.2 mm)
Neck diameter	.423 in (10.7 mm)
Shoulder diameter	.423 in (10.7 mm)
Base diameter	.424 in (10.8 mm)
Rim diameter	.424 in (10.8 mm)
Rim thickness	.055 in (1.4 mm)
Case length	.850 in (21.6 mm)
Overall length	1.135 in (28.8 mm)
Case capacity	19.3 gr H2O (1.255 cm³)
Rifling twist	1 in 16 in. (406 mm)
Primer type	Small Pistol
Maximum pressure	35,000 psi (240 MPa)
Ballistic performance
Bullet weight/type	Velocity	Energy
135 gr (8.7 g) Federal Premium JHP Reduced Recoil	1,190 ft/s (360 m/s)	424 ft·lbf (575 J)
155 gr (10.0 g) Guardian Gold JHP	1,205 ft/s (367 m/s)	500 ft·lbf (680 J)
165 gr (10.7 g) Remington Golden Saber	1,150 ft/s (350 m/s)	485 ft·lbf (658 J)
180 gr (12 g) Magtech FMJ-FP	1,050 ft/s (320 m/s)	441 ft·lbf (598 J)
200 gr (13 g) Doubletap FMJ-FP	1,050 ft/s (320 m/s)	490 ft·lbf (660 J)
Test barrel length: 4 in. Source(s): [1][2]

The .40 S&W (10×22mm Smith & Wesson) is a rimless pistol cartridge developed jointly by major American firearms manufacturers Smith & Wesson and Winchester.^[3] The .40 S&W was developed from the ground up as a law enforcement cartridge designed to duplicate performance of the Federal Bureau of Investigation's reduced-velocity 10mm Auto cartridge which could be retrofitted into medium-frame (9mm size) automatic handguns. It uses .40 inch (10.16mm) diameter bullets ranging in weight from 105 to 200 grains (6.8039 g to 13 g).^[4]

History[link]

In the aftermath of the 1986 F.B.I. Miami shootout, the F.B.I. started the process of testing 9mm and .45 ACP ammunition in preparation to replace its standard issue revolver with a semi-automatic pistol. The semi-automatic pistol offered two advantages over the revolver: 1) the semi-automatic offered increased ammunition capacity, and 2) it was easier to reload during a gunfight. The F.B.I. was satisfied with the performance of its .38 Special +P 158 gr (10.2 g) L.S.W.C.H.P. cartridge ("F.B.I. Load") based on decades of dependable performance. Ammunition for the new semi-automatic pistol had to deliver terminal performance equal or superior to the .38 Special F.B.I. Load. The F.B.I. developed a series of practically oriented tests involving eight test events that reasonably represented the kinds of situations that F.B.I. agents commonly encounter in shooting incidents.

During tests of the 9mm and .45 ACP ammunition, the F.B.I. Firearms Training Unit's Special Agent-in-Charge John Hall decided to include tests of the 10mm cartridge, supplying his personally owned Colt Delta Elite 10mm semi-automatic, and personally handloaded ammunition. The F.B.I.'s tests revealed that a 170–180 gr (11–12 g) JHP 10mm bullet, propelled between 900–1,000 ft/s (270–300 m/s), achieved desired terminal performance without the heavy recoil associated with conventional 10mm ammunition (1,300–1,400 ft/s (400–430 m/s)). The F.B.I. contacted Smith & Wesson and requested it to design a handgun to F.B.I. specifications, based on the existing large-frame S&W Model 4506 .45 ACP handgun, that would reliably function with the F.B.I.'s reduced velocity 10mm ammunition. During this collaboration with the FBI, S&W realized that downloading the 10mm full power to meet the F.B.I. medium velocity specification meant less powder and more airspace in the case. They found that by removing the airspace they could shorten the 10 mm case enough to fit within their medium-frame 9mm handguns and load it with a 180 gr (12 g) JHP bullet to produce ballistic performance identical to the FBI's reduced velocity 10mm cartridge. S&W then teamed with Winchester to produce a new cartridge, the .40 S&W. It uses a small pistol primer whereas the 10mm cartridge uses a large pistol primer.

The .40 S&W cartridge debuted January 17, 1990, along with the new Smith & Wesson Model 4006 pistol, although it was several months before the pistols were available for purchase. Austrian manufacturer Glock Ges.m.b.H. beat Smith & Wesson to the dealer shelves in 1990, with pistols chambered in .40 S&W (the Glock 22 and 23) which were announced a week before the 4006.^[5] Glock's rapid introduction was aided by its engineering of a pistol chambered in 10mm Auto, the Glock 20, only a short time earlier. Since the .40 S&W uses the same bore diameter and case head as the 10mm Auto, it was merely a matter of adapting the 10mm design to the shorter 9×19mm Parabellum frames. The new guns and ammunition were an immediate success.^[6][7]

The .40 S&W case length and overall cartridge length are shortened, but other dimensions except case web and wall thickness remain identical to the 10mm Auto. Both cartridges headspace on the mouth of the case. Thus in a semi-auto they are not interchangeable. Fired from a 10mm pistol the .40 Smith & Wesson cartridge will headspace on the extractor and the bullet will jump a .142 inch freebore just like a .38 Special fired from a .357 Magnum pistol. If the cartridge is not held by the extractor, the chances for a ruptured primer are great.^[8] Smith and Wesson does make a double action revolver that can fire either at will using moon clips. A single-action revolver in the .38–40 chambering can also be modified to fire the .40 or the 10 mm if it has an extra cylinder. Most .40 caliber handguns can be easily converted to 9mm for cheaper target shooting with a simple barrel and magazine swap.^[9][10]

Israel Military Industries attempted a similar cartridge in the 1980s, called the .41 Action Express (or .41 AE) for the Jericho 941 pistol.^[6] This cartridge was based on a new proprietary case with a 9mm base and 41 caliber suitable main case body. The .41 AE is ballistically similar to the .40 S&W, to the point that some handloading manuals suggest using .40 S&W load data in the .41 AE. The .41 AE uses 0.410-inch (10.4 mm) bullets, whereas the .40 S&W uses 0.400-inch (10.2 mm) bullets. However, as it lacks the backing of ammunition manufacturers in making .410 caliber bullets suited to semi-automatic pistols, the .41 AE has not achieved widespread popularity.^[11][12]

Cartridge dimensions[link]

The .40 S&W has 1.25 ml (19.3 grains H₂O) cartridge case capacity.

.40 S&W maximum C.I.P. cartridge dimensions.^[2] All sizes in millimeters (mm).

The common rifling twist rate for this cartridge is 406 mm (1 in 16 in), 6 grooves, ∅ lands = 9.91 mm, ∅ grooves = 10.17 mm, land width = 3.05 mm and the primer type is small pistol.^[4] According to the official C.I.P. (Commission Internationale Permanente Pour L'Epreuve Des Armes A Feu Portative) guidelines the .40 S&W case can handle up to 225 MPa (32,633 psi) piezo pressure. In C.I.P. regulated countries every pistol cartridge combo has to be proofed at 130% of this maximum C.I.P. pressure to certify for sale to consumers.
The S.A.A.M.I. pressure limit for the .40 S&W is set at 241.32 MPa (35,000 psi), piezo pressure.^[11]

Performance[link]

The .40 S&W cartridge has been popular with law enforcement agencies in the United States, Canada, and Australia. While possessing nearly identical accuracy,^[13] drift and drop, it has an energy advantage over the 9×19mm Parabellum, and with a more manageable recoil than the 10 mm Auto cartridge.^[6] Marshall & Sanow (and other hydrostatic shock proponents) contend that with good JHP bullets, the more energetic loads for the .40 S&W can also create hydrostatic shock in human-sized living targets.^[14][15]

Based on ideal terminal ballistic performance in ordnance gelatin during lab testing in the late 1980s and early 1990s, the .40 S&W earned status as "the ideal cartridge for personal defense and law enforcement".^[7][16]. Apart from the imperfect relationship between ordnance gelatin ballistics and actual stopping power, critics pointed to the reduced power of the round compared with the 10 mm Auto it was based on. Ballistically the .40 S&W is almost identical to the .38-40 Winchester introduced in 1874, as they share the same bullet diameter, bullet weight, and similar muzzle velocity^[17]. The energy of the .40 S&W exceeds standard-pressure .45 ACP loadings, generating between 350-foot-pound (470 J) and 500-foot-pound (680 J) of energy, depending on bullet weight. Both the .40 S&W and the 9 mm Parabellum operate at a 35,000 psi (240 MPa) SAAMI maximum, compared to a 21,000 psi (150 MPa) maximum for .45 ACP.^[18]

The 9 mm Parabellum remains the dominant pistol cartridge for military and law enforcement in the western world. Select U.S. special operations units, have available the .40 S&W and .45 ACP for their pistols. The United States Coast Guard, have dual duties as maritime law enforcement and military deployments, has adopted the SIG Sauer P229R DAK in .40 S&W as their standard sidearm. The Beretta M9, 9mm pistol is also in service with the U.S. Navy and some U.S. Coast Guard units.

The .40 S&W was originally loaded at subsonic velocity (around 980 ft/s (300 m/s)) with a 180 grain bullet.^[16] Since its introduction, various loads have been created, with the majority being either 155 gr (10.0 g), 165 gr (10.7 g) or 180 gr (12 g).^[19] However, there are some bullets with weights as light as 135 grain and as heavy as 200 gr (13 g). Cor-Bon and Winchester both offer a 135 gr (8.7 g) JHP and Cor-Bon also offers a 140 gr (9.1 g) Barnes XPB hollow-point. Double Tap Ammo, based out of Cedar City, Utah loads a 135 gr (8.7 g) Nosler JHP, a 155 gr (10.0 g), 165 gr (10.7 g) and 180 gr (12 g) Speer Gold Dot hollow-point (marketed as "Bonded Defense"), a 180gr Hornady XTP JHP, and three different 200gr loads included a 200 gr (13 g) Full Metal Jacket (FMJ), a 200 gr (13 g) Hornady XTP JHP and Double Tap's own 200 gr (13 g) WFNGC (Wide Flat Nose Gas Check) hard cast lead bullet; the latter specifically designed for hunting and woods carry applications.^[20]

The table below shows common performance parameters for several .40 S&W loads. Bullet weights from 135 to 180 grains are common.^[7] Loads are available with energies from just over 360 ft·lbf (490 J) to over 550 ft·lbf (750 J), and penetration depths from 9.8 inches (250 mm) to 25 inches (640 mm) are available for various applications and risk assessments.

Key:
Expansion: expanded bullet diameter (ballistic gelatin).
Penetration: penetration depth (ballistic gelatin).
PC: permanent cavity volume (ballistic gelatin, FBI method).
TSC: temporary stretch cavity volume (ballistic gelatin).

Case failure reports[link]

Beretta 96 Feed Ramp

The .40 S&W has been noted in a number of cartridge case failures, particularly in older Glock pistols due to the relatively large area of unsupported case head in those barrels, given its high working pressure.^[22][23] The feed ramp on the Glock .40 S&W pistols is larger than on other Glocks, which leaves the rear bottom of the case unsupported, and it is in this unsupported area that the cases fail. Most, but not all, of the failures have occurred with reloaded or remanufactured ammunition.^[24] Cartridges loaded at or above the SAAMI pressure, or slightly oversized cases which fire slightly out of battery are often considered to be the cause of these failures.^[24] Many competition shooters who reload for the .40 S&W will utilize a heavier than factory tension recoil spring to increase the lock time of the slide and prevent potential issues with early slide lock release.^[25] These failures are commonly referred to as "kaBooms" or "kB!" for short.^[24] While these case failures do not often injure the person holding the pistol, the venting of high pressure gas tends to eject the magazine out of the magazine well in a spectacular fashion, and usually destroys the pistol. In some cases, the barrel will also fail, blowing the top of the chamber off.

Beretta 96 Extractor Notch

While the .40 S&W is far from being the only cartridge to suffer from case failures, it is more susceptible for a number of reasons. The .40 S&W works at relatively high pressures (33,000 psi/230 MPa typical, but 35,000 psi/240 MPa SAAMI max). Since the .40 S&W is a wide cartridge for its length, and is often adapted to frames designed for the equally long but narrower 9x19mm cartridge, the length of the feed ramp must be longer to provide the same angle, which causes the feed ramp to extend into the chamber. This in turn leaves more of the case head unsupported, reducing the margin of safety. When exacerbated by out of battery firing (leaving even more case head exposed) and potentially weakened brass (due to reloading) these factors appear to lead to the higher incidents of chamber failure. The number of case failures in the .40 S&W is serious enough that Accurate Arms no longer recommends reloading of .40 S&W cartridges for firearms without complete case head support.^[26]

In late 1995, Federal Cartridge of Anoka, Minnesota undertook a redesign of their .40 S&W cartridge case to strengthen internally the area of the case web. While no one at Federal will address this for the record, it has been suggested that this move was dictated by the popularity of the .40 S&W Glocks, and Federal's attempt to hedge against head/web ruptures with any of their .40 S&W ammunition.

Federal .40 S&W rounds which may contain suspect casings may be identified as follows: Lot number consists of 10 characters (mostly numbers). In the 7th position, there may be a number or a letter. If there is a number in that position, the ammo was manufactured with the old style (possibly defective) brass. If it contains the letter Y (1995) or R (1996), the ammo has the redesigned casing and should be okay. If the letter H appears, then check the next three digits (the last three in the lot number). Ammo lot numbers H244 or below have the old style casings. Lots H245 and above have the new style casings.

This information was provided by Federal Cartridge Company in September 1996.

Writer Walt Rauch first brought forth information that bullet set-back (such as often occurs in administrative unloading/loading) in the .40 S&W could raise pressures exponentially. Rauch published some specific information on this set-back issue in the May/June 2004 Police and Security News, in a feature entitled Why Guns Blow Up!: "The simple chambering and rechambering of a cartridge does push the bullet back into its case."

Hirtenberg Ammunition Company of Austria (at the request of GLOCK, Inc.) determined that, with a .40 caliber cartridge, pushing the bullet back into the case 1/10 of an inch doubled the chamber pressure. This is higher than a proof load. This can occur with but one chambering since it is dependent on how well the case was crimped or sealed to the bullet.

Synonyms[link]

• .40
• .40 Smith
• .40 S&W
• .40 Short & Weak (the term favored by Jeff Cooper, comparing the cartridge to the full-house 10mm Auto from which it is derived)
• .40 Auto
• .40 Slow & Weighty (a reference to a proposed 200 grain offering with less recoil and high effectiveness)
• .40 caliber or "Forty cal"
• .40 Liberty (promoted by L. Neil Smith as part of a boycott of Smith & Wesson for making an agreement with the U.S. Government under President Bill Clinton.)^[27][28]
• 10 mm Kurz (10 mm Short)

See also[link]

• 10mm Auto
• List of handgun cartridges
• List of firearms

References[link]

External links[link]

• Ballistics By The Inch .40 S&W Results

Wikimedia Commons has media related to: .40 S&W

S. W. R. D. Bandaranaike
4th Prime Minister of Sri Lanka
In office 1956–1959
Monarch	Elizabeth II
Preceded by	John Lionel Kotalawela
Succeeded by	Wijeyananda Dahanayake
Personal details
Born	January 8, 1899 Ceylon
Died	September 26, 1959(1959-09-26) (aged 60) Colombo, Sri Lanka (assassinated)
Nationality	Ceylonese
Political party	Sri Lanka Freedom Party
Spouse(s)	Sirimavo Bandaranaike
Profession	Politician, Barrister
Religion	Theravada Buddhism

Solomon West Ridgeway Dias Bandaranaike (Sinhala:සොලමන් වෙස්ට් රිජ්වේ ඩයස් බන්ඩාරනායක) (Tamil:சாலமன் வெஸ்ட் ரிச்சர்ட் டயஸ் பண்டாரநாயக்கா) (frequently referred to as S.W.R.D. Bandaranaike; January 8, 1899 – September 26, 1959) was the fourth Prime Minister of Ceylon (later Sri Lanka), serving from 1956 until his assassination by a Buddhist monk in 1959.^[1][2][3]

Early life & education[link]

Bandaranaike attended Christ Church College, Oxford, gaining a reputation as a fiery orator when he participated in debates with the Oxford Union. He was elected Secretary of the Oxford Union.

Bandaranaike was born in Colombo, Ceylon to an elite Sinhalese Anglican Christian family and was the son of the powerful Sir Solomon Dias Bandaranike the Maha Mudaliyar (the chief native interpreter and advisor to the Governor) of Horagolla Walauwa in Atthanagalla, during British colonial rule. In later life he converted to Buddhism in order to join politics.^[4] He received his secondary education at St Thomas' College and went on to study at Christ Church, Oxford University, where he was Secretary of the famous Oxford Union. He later qualified as a Barrister in England.

Political career[link]

As a young lawyer Bandaranaike became active in the Ceylon National Congress (CNC). He was elected to the Colombo Municipal Council in 1926. From 1931 to 1947 he served in the State Council of Ceylon. In order to promote Sinhala culture and community interests, Bandaranaike organised the Sinhala Maha Sabha in 1936.^[5] In 1946 he backed the United National Party (UNP) and held ministerial posts from 1947 to 1951. In 1951, Bandaranaike led his Sinhala Maha Sabha faction out of the UNP and established the Sri Lanka Freedom Party (SLFP).^[6]

On the sensitive issue of language, the party originally espoused the use of both Sinhala and Tamil as national languages, but in the mid-1950s it adopted a "Sinhala only" policy. The party asserts it is a champion of the Buddhist religion, which had been attacked by local Christians and Tamils alike during the colonial era. The SLFP has customarily relied upon the socially and politically influential Buddhist clergy, the sangha, to carry its message to the Sinhala villages. Since the 1950s, SLFP platforms have reflected the earlier organization's emphasis on appealing to the sentiments of the Sinhala masses in rural areas. To this basis has been added the anti-establishment appeal of non-revolutionary socialism.

Bandaranaike became prime minister after winning the 1956 elections in a landslide, at the head of a four-party coalition with a no-contest pact with the Lanka Sama Samaja Party and the Communist Party of Sri Lanka. As such, he made Sinhala the official language of the country, downgrading the official status of English and promoting socialist, non-Western policies that profoundly changed the course of Ceylonese politics in the following decades.

As prime minister, he took a neutralist stance in foreign affairs. He removed the British air bases at Katunayake and China Bay and the naval base at Trincomalee. Domestically, he was faced by economic problems and disputes over languages. He is also remembered by the minority Sri Lankan Tamils for his failure to use the state's resources to control the 1958 riots, leading to many deaths of Tamil people at the hands of mobs.

Assassination[link]

In the 3rd year in office he died on 26 September 1959, at the age of 60, at the Merchant's Ward of the Colombo General Hospital due to wounds received after being shot by Talduwe Somarama.

The day before, 25 September, Somarama visited Bandaranaike at his private residence, Tintagel, in Rosmead Place, Colombo. Since Somarama was a member of the Buddhist clergy, he was not searched for weapons and given free access to the prime minister as he began his routine meetings with the public. When the monk's presence was intimated to him, Bandaranaike rose to greet him in the traditional Buddhist manner. The assassin then plucked out the revolver hidden in his robes and fired at the prostrate prime minister. The wounded Bandaranaike was rushed to hospital but died the following day in spite of a six hour surgery by Ceylon's most skilled surgeons.^{[citation needed]}

After Bandaranaike's death, Wijeyananda Dahanayake, minister of education and the leader of the House took over as care taker prime minister after being appointed by the Ceylonese parliament. However he fell out of favor with the members of the government, resulting the removal of all ministers of the Bandaranaike's cabinet in less than a year. Eventually the leadership of the Sri Lanka Freedom Party fell to Bandaranaike's widow Sirimavo Ratwatte Dias Bandaranaike who was soon appointed a Senator. She became the world's first female Prime Minister when another coalition led by the SLFP won elections in July 1960.

Family life[link]

He married Sirimavo Ratwatte in 1940 and the marriage produced three children. Sirimavo Ratwatte Dias Bandaranaike, as she was known after her marriage, became the first female prime minister in the world following his assassination. His second daughter Chandrika Kumaratunga, subsequently became Prime Minister (1994) and the first female Executive president in the country, his youngest son Anura Bandaranaike went on to become Speaker of the Parliament of Sri Lanka (1999–2001) and a Minister (2004–2008) and his eldest Sunethra Bandaranaike is a prominent philanthropist.

See also[link]

• Bandaranaike-Chelvanayakam Pact
• List of political families in Sri Lanka

Footnotes[link]

References[link]

• Nyrop, Richard (1982). Sri Lanka, a Country Study. Supt. of Docs., U.S. G.P.O.. 

External links[link]

• The Bandaranaike Museum
• The Bandaranaike Ancestry
• The Ratwatte Ancestry
• Golden memories of a political prodigy
• Commemorating the Bandaranaikes: The emergence of the political middle-class
• The Pensive Premier
• 49 years after S.W.R.D. Bandaranaike
• Trail-Blazing Leader
• The Great son of Sri Lanka
• Website of the Parliament of Sri Lanka
• Sri Lanka Freedom Party's official Website

This page incorporates text from the Library of Congress's Country Studies series.

v t e Prime Ministers of Sri Lanka D.S. Senanayake • Dudley Senanayake • John Kotelawala • S.W.R.D. Bandaranaike • W. Dahanayake • Dudley Senanayake • Sirimavo Bandaranaike • Dudley Senanayake • Sirimavo Bandaranaike • J.R. Jayewardene • Ranasinghe Premadasa • D.B. Wijetunga • Ranil Wickremasinghe • Chandrika Kumaratunga • Sirimavo Bandaranaike • Ratnasiri Wickremanayake • Ranil Wickremasinghe • Mahinda Rajapaksa • Ratnasiri Wickremanayake • D. M. Jayaratne

v t e // Members of 1st Parliament of Ceylon (1947 (1947)-1952) → Speaker: Alfred Molamure/Albert F. Peries Prime Minister: Don Stephen Senanayake/Dudley Senanayake Leader of the Opposition: N. M. Perera S. W. R. D. Bandaranaike P. B. Bulankulame S. J. V. Chelvanayakam Colvin R. de Silva A. E. Goonesinha Philip Gunawardena Junius Richard Jayewardene Pieter Keuneman Alfred Francis Molamure E. A. Nugawela N. M. Perera Wilmot A. Perera Albert F. Peries G. G. Ponnambalam Abeyratne Ratnayaka J.A. Martenze Don Stephen Senanayake Dudley Senanayake Cathiravelu Sittampalam Savumiamoorthy Thondaman T. B. Jayah Arthur de Zoysa *This list is unfinished.

v t e ← Members of 2nd Parliament of Ceylon (1952 (1952)-1956) → Speaker: Albert F. Peries Prime Minister: Dudley Senanayake/John Kotelawala Leader of the Opposition: S. W. R. D. Bandaranaike S. W. R. D. Bandaranaike Razik Fareed Junius Richard Jayewardene C. W. W. Kannangara Pieter Keuneman John Kotelawala Subaiya Nadesan Wilmot A. Perera Albert F. Peries G. G. Ponnambalam Dudley Senanayake Cathiravelu Sittampalam *This list is unfinished.

v t e ← Members of 3rd Parliament of Ceylon (1956 (1956)-1959) → Speaker: H. S. Ismail Prime Minister: S. W. R. D. Bandaranaike/Wijeyananda Dahanayake Leader of the Opposition: N. M. Perera Appapillai Amirthalingam S. W. R. D. Bandaranaike S. J. V. Chelvanayakam Wijeyananda Dahanayake Colvin R. de Silva Stanley de Zoysa Razik Fareed H. S. Ismail P.B.G. Kalugalla Pieter Keuneman Anil Moonesinghe V. N. Navaratnam N. M. Perera G. G. Ponnambalam Richard Gotabhaya Senanayake *This list is unfinished.