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.40 S&W

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.40 S&W
.40 S&W compared to other cartridges (third from right).
TypePistol
Place of origin United States
Production history
DesignerSmith & Wesson
DesignedJanuary 17, 1990
Produced1990 to present
Specifications
Parent case10 mm Auto
Case typeRimless, straight
Bullet diameter.4005 in (10.17 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 length1.135 in (28.8 mm)
Case capacity19.3 gr H2O (1.25 cm3)
Rifling twist1 in 16 in (406 mm)
Primer typeSmall pistol
Maximum pressure32,633 psi (225.00 MPa)
Ballistic performance
Bullet mass/type Velocity Energy
135 gr (9 g) Federal Premium JHP Low Recoil 1,190 ft/s (360 m/s) 424 ft⋅lbf (575 J)
155 gr (10 g) Speer Gold Dot JHP 1,175 ft/s (358 m/s) 475 ft⋅lbf (644 J)
165 gr (11 g) Speer Gold Dot JHP 1,150 ft/s (350 m/s) 484 ft⋅lbf (656 J)
180 gr (12 g) Speer Gold Dot JHP 985 ft/s (300 m/s) 400 ft⋅lbf (540 J)
200 gr (13 g) Double Tap Hornady XTP JHP 1,050 ft/s (320 m/s) 490 ft⋅lbf (660 J)
Test barrel length: 4 in
Source(s): Midway USA page C.I.P.[1]

The .40 S&W (10x22mm Smith & Wesson) is a rimless pistol cartridge developed jointly by major American firearms manufacturers, Winchester and Smith & Wesson.[2] The .40 S&W was developed from the ground up as a law enforcement cartridge designed to duplicate performance of the FBI's reduced velocity 10mm cartridge which could be retrofitted into medium-frame (9mm size) automatic handguns. It uses .40-inch (10.16 mm) diameter bullets ranging in weight from 135 to 200 grains (9 g to 13 g).[3] A number of loads with hollow point bullets offer a good combination of expansion, penetration, temporary cavitation, and sufficient energy transfer to impart hydrostatic shock.[4][5]

History

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

During tests of 9mm and .45 ACP ammunition, FBI Firearms Training Unit, Special Agent In Charge, John Hall, decided to include tests of the 10mm cartridge, supplying his personally owned Colt Delta Elite 10mm automatic, and personally handloading 10mm ammunition. The FBI's tests revealed that a 170-180gr JHP 10mm bullet, propelled between 900-1000 fps, achieved desired terminal performance without the heavy recoil associated with conventional 10mm ammunition (1300-1400 fps). The FBI contacted Smith & Wesson and requested it to design a handgun to FBI specifications, based on the existing large-frame S&W 4506 .45 ACP handgun, that would reliably function with the FBI's reduced velocity 10mm ammunition. During this collaboration with the FBI, S&W realized it could shorten the 10mm case enough to fit within its medium-frame 9mm handguns and load it with a 180gr 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 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.[6] Glock's rapid introduction was aided by its engineering of a pistol chambered in 10 mm Auto, the Glock 20, only a short time earlier. Since the .40 S&W uses the same bore diameter and case head as the 10 mm Auto, it was merely a matter of adapting the 10 mm design to the shorter 9x19mm frames. The new guns and ammo were an immediate success.[7][8]

The 40 S&W case length and overall cartridge length are shortened, but other dimensions, except case web, remain identical to the 10mm Auto. Both cartridges headspace on the mouth of the case. Thus in a semi-auto they are not interchangeable. 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. The .40 will at short range take deer; it is also suitable for small and medium game. Most .40 caliber handguns can be easily converted to 9MM for cheaper target shooting with a simple barrel and magazine swap.[9][10]

IMI attempted a similar cartridge in the 1980s, called the .41 Action Express (or .41 AE) for the Jericho 941 pistol.[7] This cartridge was based on a new proprietary case with a 9MM base and 41 caliber suitable main case body. The .41 AE is ballisticaly similar to the .40 S&W, to the point that some reloading manuals suggest using .40 S&W load data in the .41 AE. The .41 AE was a poor design because the small rim and larger and higher energy .41 case beats the 9MM rim/base up badly. Case life for reloading is relatively short. The .41 AE is for all intents and purposes, now an obsolete and difficult to obtain caliber. 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

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

Some .40 S&W dimensions in the drawing have to be corrected:
E = 3,52 mm
delta = 45,00 degrees
beta = 35,00 degrees

.40 S&W maximum C.I.P. cartridge dimensions.[1] All sizes in millimeters (mm).

The common rifling twist rate for this cartridge is 406 mm (1 in 16 in), 6 grooves, Ø lands = 9.91 mm, Ø grooves = 10.17 mm, land width = 3.05 mm and the primer type is small pistol.[3] 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 SAAMI pressure limit for the .40 S&W is set at 241.32 MPa (35,000 psi), piezo pressure.[11]

Performance

The .40 S&W cartridge has been successful in the United States because, while possessing nearly identical accuracy,[13] drift and drop, it has a slight energy advantage over the 9 mm Parabellum with a more manageable recoil than the 10 mm Auto cartridge.[7] With good JHP bullets in the more energetic loads (> 500 ft·lbf) the .40 S&W can create hydrostatic shock in human-sized living targets.[4][14]

The .40 S&W has been called “the ideal cartridge for personal defense and law enforcement,”[15] and a ”lot more than a 9mm.”[8] On the other hand, critics pointed to the reduced power of the round compared with the 10 mm Auto it was based on leading to derogatory names such as ".40 Short and Wimpy" or ".40 Slow and Weak". The energy of the .40 S&W exceeds standard-pressure 9x19mm Parabellum and .45 ACP loadings, generating between 350 and 500 foot-pounds 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.[16] While SAAMI has not established a +P standard for the .40 S&W, there are companies marketing ammunition claimed to be +P, but they do not provide pressure data to support +P labeling.

Despite the .40 S&W's popularity amongst American law enforcement and the private sector, it has yet to be adopted by a significant number of military forces worldwide.[citation needed] The mainstay for military use in the western world largely remains the preserve of the 9 mm Parabellum, or for a few US special forces, .45 ACP in their respective adopted handguns. The United States Coast Guard, which performs Maritime Law Enforcement duties however, has adopted the Sig Sauer P229R DAK in .40 S&W as their standard sidearm.

File:40AITvsBPW.png
Comparison of incapacitation times (170 lb. males shot in the center of the chest) vs. ballistic pressure waves for some 9x19mm and .40 S&W loads.[17]

The .40 S&W was originally loaded at subsonic velocity (around 980 fps) with a 180 grain bullet.[15] Since its introduction, various loads have been created, with the majority being either 155, 165 or 180 grain.[18] However, there are some bullets with weights as light as 135 grain and as heavy as 200 grain. Cor-Bon offer a 135 grain JHP as well as a 140 grain Barnes XPB hollow-point. Double Tap Ammo, based out of Cedar City, Utah loads a 135gr Nosler JHP, a 155gr, 165gr and 180gr Speer Gold Dot hollow-point (marketed as "Bonded Defense"), a 180gr Hornady XTP JHP, and three different 200gr loads included a 200gr Full Metal Jacket (FMJ), a 200gr Hornady XTP JHP and Double Tap's own 200gr WFNGC (Wide Flat Nose Gas check) hard cast lead bullet; the latter specifically designed for hunting and woods carry applications.[19]

The table below shows common performance parameters for several .40S&W loads. Bullet weights from 135 to 180 grains are common.[8] Loads are available with energies from just over 360 ft·lbf to over 550 ft·lbf, and penetration depths from 9.8 inches to 25 inches are available for various applications and risk assessments.

Manufacturer Load Mass (grains) Velocity (ft/s) Energy (ft·lbf) Expansion (inches)[20] Penetration (inches)[20] BPW[21] (psi) PC[20] (cu in) TSC[20] (cu in) OSS[22] AIT[21] (sec)
Cor-Bon JHP 135 1300 507 0.56 9.8 1384 2.4 69.1 89.3% 5.9
Double Tap Gold Dot JHP 155 1275 559 0.76 13.0 822 5.9 48.5 (est) 88.9%[23] 7.7
Federal HydraShok JHP 155 1140 447 0.68 13.3 642 4.8 47.9 93.2% 8.7
Remington Golden Saber JHP 165 1150 485 0.68 12.0 771 4.4 41.1 93.8% 7.9
Winchester Ranger SXT 180 990 392 0.72 13.0 576 5.3 29.1 80.0% 9.2
Winchester FMJ 180 950 361 0.40 25.0 276 3.1 14.6 71.3% 13.2

Key: Expansion – expanded bullet diameter (ballistic gelatin). Penetration – penetration depth (ballistic gelatin). BPW – ballistic pressure wave associated with remote wounding effects known as hydrostatic shock. PC – permanent cavity volume (ballistic gelatin, FBI method). TSC – temporary stretch cavity volume (ballistic gelatin). OSS – Marshall and Sanow “one-shot stop” rating. AIT – Average incapacitation time, time from unobstructed hit in the center of the chest until incapacitation for 170 lb male as determined from ballistic pressure wave model.

Prior to transitioning to .40 S&W, California Highway Patrol (CHP), the first large agency to adopt .40 S&W, used a variety of .357 Magnum loads, depending upon what was available via the state contract. According to published CHP test data, the .357 Magnum load used immediately prior to the CHP transition to .40 S&W was the Remington 125 gr SJHP with an average muzzle velocity of 1450 f/s from their duty revolvers. Yet despite the decrease in velocity, CHP has continued to report greater success in officer-involved shooting incidents (both better terminal performance, as well as intermediate barrier ability) with their .40 S&W 180 gr JHP than with the .357 Magnum 125 gr SJHP they previously issued.

Case failure reports

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.[24] The feed ramp on the Glock .40 S&W pistols are larger than normal, 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. 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. These failures are referred to by many as "kaBooms" or "kB!" for short. 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 the only cartridge to suffer from case failures, it is more susceptible for a number of reasons. The .40 S&W works at fairly high pressures (33,000 psi/230 MPa typical, but 35,000 psi/240 MPa SAAMI max) for a large caliber handgun cartridge, significantly more than, say, the .45 ACP.[25] 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. While this is not necessarily unsafe, it does reduce 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]

Synonyms

See also

References

  1. ^ a b "C.I.P. decisions, texts and tables - free current C.I.P. CD-ROM version download (ZIP and RAR format)". Retrieved 2008-10-17.
  2. ^ "Taffin Tests: The .40 S&W". Retrieved 2007-09-25.
  3. ^ a b Hornady Handbook of Cartridge Reloading, Fourth Edition (1991), pp. 593-595 Cite error: The named reference "”Hornady”" was defined multiple times with different content (see the help page).
  4. ^ a b Hollow-point ammunition and handguns: The potential for large temporary cavities, Fernando Spencer Netto, Dylan Pannell, Homer C. Tien, Injury Extra (2008) 39, 50—52 Cite error: The named reference "”Tien2008”" was defined multiple times with different content (see the help page).
  5. ^ Street Stoppers, E. Marshall and E. Sanow, Paladin (1996) pp. 25-58
  6. ^ "The .40 Smith & Wesson: this round came along at the right time in the right place". Retrieved 2007-09-25.
  7. ^ a b c Speer Reloading Manual Number 12 (1994) pp. 534-542. Cite error: The named reference "”Speer”" was defined multiple times with different content (see the help page).
  8. ^ a b c Nosler Reloading guide Number Four (1996) pp. 529-534. Cite error: The named reference "”Nosler”" was defined multiple times with different content (see the help page).
  9. ^ "Smith & wesson model compact: Good looking and great shooting, petty finds that there is a lot to like about this new offering from the S&W performance center". Retrieved 2007-09-25.
  10. ^ "Gossip, finger-pointing and whispers". Retrieved 2007-09-25.
  11. ^ a b "SAAMI Pressures". Retrieved 2007-11-29.
  12. ^ ".40 Smith & Wesson/.41 AE" (PDF). Retrieved 2007-11-29.
  13. ^ "New Life For An Old Cat (Stoeger Model 8000 Cougar)". Retrieved 2007-09-25.
  14. ^ Street Stoppers, E. Marshall and E. Sanow, Paladin (1996) pp. 25–58.
  15. ^ a b Marshall and Sanow, Street Stoppers, Paladin (1996) pp. 115–131.
  16. ^ "SAAMI Pressure specifications". Retrieved 2007-09-25.
  17. ^ AIT computed with hypothetical model from Courtney A, Courtney M: Links between traumatic brain injury and ballistic pressure waves originating in the thoracic cavity and extremities. Brain Injury 21(7): 657–662, 2007.
  18. ^ Stopping Power, E. Marshall and E. Sanow, Paladin (2001), pp. 49–58.
  19. ^ http://www.doubletapammo.com/php/catalog/index.php?cPath=21_26
  20. ^ a b c d Marshall and Sanow, Street Stoppers, Appendix A, Paladin 1996.
  21. ^ a b From model in Courtney A, Courtney M: Links between traumatic brain injury and ballistic pressure waves originating in the thoracic cavity and extremities. Brain Injury 21(7): 657–662, 2007.
  22. ^ Marshall and Sanow, Street Stoppers, Appendix A, Paladin 1996; also Marshall and Sanow, Stopping Power, Paladin 2001.
  23. ^ Estimated from model in Courtney and Courtney http://arxiv.org/ftp/physics/papers/0701/0701266.pdf
  24. ^ ".40 S&W Case Failures in Glocks". Retrieved 2007-09-25.
  25. ^ "SAAMI Pressures". Retrieved 2007-09-25.
  26. ^ "Safety". Accurate Arms.
  27. ^ 40S&W Name Change 40 Liberty+++ [Archive] - TheFiringLine Forums
  28. ^ Smith & Wesson Must Die, by L. Neil Smith

External links

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