.40 S&W

From Wikipedia, the free encyclopedia

Jump to: navigation, search
.40 S&W
CartridgeComparison.jpg
.40 S&W compared to other cartridges (third from right).
Type Pistol
Place of origin  United States
Production history
Designer Smith & Wesson
Designed January 17, 1990
Produced 1990 to present
Specifications
Parent case 10 mm Auto
Case type Rimless, 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 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 32,633 psi (225.00 MPa)
Ballistic performance
Bullet weight/type Velocity Energy
135 gr (8.7 g) Federal Premium JHP Low Recoil 1,190 ft/s (360 m/s) 424 ft·lbf (575 J)
155 gr (10.0 g) Speer Gold Dot JHP 1,175 ft/s (358 m/s) 475 ft·lbf (644 J)
165 gr (10.7 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: Midway USA page C.I.P.[1]

The .40 S&W (10x22mm Smith & Wesson) is a rimless pistol cartridge developed jointly by Winchester and Smith & Wesson, two famous American firearms manufacturers.[2] It uses .40-inch (10.16 mm) diameter bullets ranging in weight from 135 to 200 grains (9 g to 13 g) and operates at about 33,000 psi (230 MPa) pressure. The .40 S&W has earned a good reputation for self-defense and police use, though it is debated whether its performance is more attributable to reliable expansion and penetration or to remote wounding effects of hydrostatic shock.[3][4][5]


Contents

[edit] History

In the aftermath of the 1986 FBI Miami shootout, the FBI started the process of upgrading their service arms to a weapon of much greater power than their collection of 9x19mm Parabellum automatics and .38 Special revolvers. This search led them to the 10 mm Auto that had been developed in the early 1980s for the famed Bren Ten, but by this point in time the company had already gone out of business. The FBI then contracted Smith & Wesson to develop a new automatic for the 10 mm Auto, creating the Smith & Wesson 1076.

After testing the new weapon, the FBI found that the recoil was too powerful to control easily, and the large rounds made the gun difficult to hold for smaller men and women. The FBI asked for several changes to the 10 mm Auto, using a reduced-charge version often referred to as the "FBI load" or "10mm lite." The case capacity of the 10 mm Auto was more than required for this "10 mm lite" load, so Smith & Wesson then redesigned the cartridge to make it shorter while maintaining the performance of the FBI loading. They also decided to use a small pistol primer, rather than the large primer used for the 10 mm Auto. With the .40 S&W being shorter than the 10 mm Auto and approximately the same overall length as the 9x19mm Parabellum cartridge, many existing 9 mm pistols could be easily adapted by their respective manufacturers to fire the new cartridge.

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 after 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.

Initial acceptance of the .40 S&W was slow, since the round was considerably less powerful than the 10 mm Auto it was based on. This led to derogatory names such as ".40 Short and Wimpy" or ".40 Slow and Weak."[7][8]

The 40 S&W is dimensionally identical to the 10 mm Auto except for case length. 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.

IMI attempted a similar cartridge in the 1980s, called the .41 Action Express (or .41 AE) for the Jericho 941 pistol. This cartridge was based on the .41 Magnum case, cut down to fit in a 9 mm frame, and using a rebated rim the same diameter as the 9 mm Luger. The .41 AE is ballistically similar to the .40 S&W, to the point that many reloading manuals suggest using .40 S&W load data in the .41 AE. The .41 AE is a more attractive cartridge in many ways, as the rebated rim allows a simple barrel and magazine change to allow most 9 mm guns to be converted to .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.[9] [10]

[edit] Cartridge dimensions

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

.40 S&W cartridge dimensions.svg

.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.

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.[9]

[edit] Performance

The .40 S&W cartridge has become a huge success in the United States because, while possessing nearly identical accuracy[11], drift and drop, it adds almost 50 percent more energy over the 9 mm Parabellum with a more manageable recoil than the 10 mm Auto cartridge. In the rest of the world it has become a popular combat pistol shooting sports cartridge.[citation needed] 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.[12]

.40 S&W Load Tables

The energy of the .40 S&W exceeds all standard-pressure and +P 9x19mm Parabellum loadings and many standard-pressure .45 ACP rounds, generating between 450 and 600 foot-pounds (550 J and 800 J) of energy, depending on bullet weight, with mid to high 500 foot-pounds force (680 N·m) typical. 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[13]. Some small ammunition manufacturers offer .40 S&W ammunition consistently developing energy well above 500 ft·lbf (700 J) in all their .40 S&W ammo as off-the-shelf items.[14]. 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 special forces, .45 ACP in their respective adopted handguns. The United States Coast Guard, however, has adopted the Sig Sauer P229R DAK in .40 S&W as their standard sidearm.

[edit] Various Loads

The .40 S&W was originally loaded at subsonic velocity (around 990fps) with a 180 grain bullet. Since its introduction, various loads have been created, with the majority being either 155, 165 or 180 grain. 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 Jack (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.

[edit] 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[15]. 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.[16] 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.[17]

[edit] Synonyms

[edit] See also

[edit] References

  1. ^ a b "C.I.P. decisions, texts and tables - free current C.I.P. CD-ROM version download (ZIP and RAR format)". http://www.cip-bp.org/index.php?id=tdcc-telechargement. Retrieved 2008-10-17. 
  2. ^ "Taffin Tests: The .40 S&W". http://www.sixguns.com/tests/tt40sw.htm. Retrieved 2007-09-25. 
  3. ^ Chamberlin FT, Gun Shot Wounds, in Handbook for Shooters and Reloaders, Vol. II, Ackley PO, ed., Plaza Publishing, Salt Lake City, Utah, 1966.
  4. ^ Sturtevant B, Shock Wave Effects in Biomechanics, Sadhana, 23: 579-596, 1998.
  5. ^ Scientific Evidence for Hydrostatic Shock http://arxiv.org/ftp/arxiv/papers/0803/0803.3051.pdf
  6. ^ "The .40 Smith & Wesson: this round came along at the right time in the right place". http://findarticles.com/p/articles/mi_m0BQY/is_9_51/ai_n14816182. Retrieved 2007-09-25. 
  7. ^ "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". http://findarticles.com/p/articles/mi_m0BQY/is_1_48/ai_80635894. Retrieved 2007-09-25. 
  8. ^ "Gossip, finger-pointing and whispers". http://findarticles.com/p/articles/mi_m0BTT/is_173_29/ai_n7578384. Retrieved 2007-09-25. 
  9. ^ a b "SAAMI Pressures". http://www.leverguns.com/articles/saami_pressures.htm. Retrieved 2007-11-29. 
  10. ^ ".40 Smith & Wesson/.41 AE". http://www.accuratepowder.com/data/PerCaliber2Guide/Handgun/Standarddata/40Cal(10mm)/40%20Smit%20Wesson%20pages%20116%20to%20118.pdf. Retrieved 2007-11-29. 
  11. ^ "New Life For An Old Cat (Stoeger Model 8000 Cougar)". http://www.gunsandammomag.com/ga_handguns/steoger8k_121106/index1.html. Retrieved 2007-09-25. 
  12. ^ "Scientific Evidence for Hydrostatic Shock". http://arxiv.org/abs/0803.3051. 
  13. ^ "SAAMI Pressure specifications". http://www.handloads.com/misc/saami.htm. Retrieved 2007-09-25. 
  14. ^ ".40 S&W 135gr Nosler JHP 50rds.". http://www.doubletapammo.com/php/catalog/product_info.php?cPath=21_26&products_id=107. Retrieved 2007-09-25. 
  15. ^ ".40 S&W Case Failures in Glocks". http://www.thegunzone.com/glock/kb-notes.html. Retrieved 2007-09-25. 
  16. ^ "SAAMI Pressures". http://www.leverguns.com/articles/saami_pressures.htm. Retrieved 2007-09-25. 
  17. ^ "Safety". Accurate Arms. http://accuratepowder.com/Safety.htm. 
  18. ^ 40S&W Name Change 40 Liberty+++ [Archive] - TheFiringLine Forums
  19. ^ Smith & Wesson Must Die, by L. Neil Smith

[edit] External links

Search Wikimedia Commons Wikimedia Commons has media related to: .40 S&W
Retrieved from "http://en.wikipedia.org/wiki/.40_S%26W"