.40 S&W

Infobox Firearm Cartridge
name=.40 S&W


caption=.40 S&W compared to other cartridges (third from right).
origin=flagcountry|United States
type=Pistol
designer=Smith & Wesson
design_date=January 17, 1990
parent=10 mm Auto
case_type=Rimless, straight
bullet=.40
neck= .423
shoulder=
base=.424
rim_dia=.424
rim_thick=.055
case_length= .850
length= 1.135
rifling=
primer=Small pistol
bw1=135
btype1=Nosler JHP
vel1=1375
en1=567
bw2=155
btype2=Gold Dot HP
vel2=1275
en2=560
bw3=165
btype3=Gold Dot HP
vel3=1200
en3=528
bw4=180
btype4=Hornady XTP
vel4=1100
en4=484
bw5=200
btype5=FMJ-FP
vel5=1050
en5=490
test_barrel_length=4 in
balsrc= [http://www.doubletapammo.com/php/catalog/index.php?cPath=21_26&osCsid=6f2191a9bfbe57e8a04b079e7ea05a58 Doubletap Ammunition Product page] The .40 S&W (10x22mm Smith & Wesson) is a rimless pistol cartridge developed jointly by Winchester and Smith & Wesson, two famous American firearms manufacturers. [cite web |url=http://www.sixguns.com/tests/tt40sw.htm |title=Taffin Tests: The .40 S&W |accessdate=2007-09-25 ] It uses .400-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.

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.

In service, the 1076 proved to be an unwieldy weapon; the recoil and muzzle blast, especially from a short barrel, were found to be too much for many shooters. 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. [cite web |url=http://findarticles.com/p/articles/mi_m0BQY/is_9_51/ai_n14816182 |title=The .40 Smith & Wesson: this round came along at the right time in the right place |accessdate=2007-09-25 ] 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 Short and Weak." [cite web |url=http://findarticles.com/p/articles/mi_m0BQY/is_1_48/ai_80635894 |title=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 |accessdate=2007-09-25 ] [cite web |url=http://findarticles.com/p/articles/mi_m0BTT/is_173_29/ai_n7578384 |title=Gossip, finger-pointing and whispers |accessdate=2007-09-25 ]

The 40 S & W is dimensionally identical to the 10 mm Auto except for 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 with loads that come close enough to the combination of .40 caliber or better, 200 grains (13 g) bullet or better, and 1,000 feet per second (300 m/s) or better. 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 .410 inch bullets, whereas the .40 S&W uses .400 inch bullets. However, as it lacks the backing of ammunition manufacturers in making .410 caliber bullets suited to semiautomatic pistols, the .41 AE has not achieved widespread popularity. [cite web |url=http://www.leverguns.com/articles/saami_pressures.htm |title=SAAMI Pressures |accessdate=2007-11-29] [cite web |url=http://www.accuratepowder.com/data/PerCaliber2Guide/Handgun/Standarddata/40Cal(10mm)/40%20Smit%20Wesson%20pages%20116%20to%20118.pdf |title=.40 Smith & Wesson/.41 AE |accessdate=2007-11-29]

Performance

The .40 S&W cartridge has become a huge success in the United States because, while possessing nearly identical accuracy [cite web |url=http://www.gunsandammomag.com/ga_handguns/steoger8k_121106/index1.html |title=New Life For An Old Cat (Stoeger Model 8000 Cougar) |accessdate=2007-09-25 ] , drift and drop, it adds 50% 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.Fact|date=July 2007 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. [cite web | url = http://arxiv.org/abs/0803.3051 |title=Scientific Evidence for Hydrostatic Shock]

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 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 [cite web |url=http://www.handloads.com/misc/saami.htm |title=SAAMI Pressure specifications |accessdate=2007-09-25 ] . 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. [cite web |url=http://www.doubletapammo.com/php/catalog/product_info.php?cPath=21_26&products_id=107 |title=.40 S&W 135gr Nosler JHP 50rds. |accessdate=2007-09-25 ] . 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.Fact|date=August 2008 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.

There are two major reasons why western military forces have not adopted the .40 S&W. The first reason is quite simply that the .40 S&W is not a NATO cartridge, and standardization is very important for logistical purposes. The second major reason for .40 S&W not being chosen by military forces is the process of adopting a new firearm, the expense of procurement, purchasing and stocking spare parts, training of weapons techs to service and repair firearms, etc. Because handguns are a secondary firearm in the military forces of any country the change over expense can not be justified by whatever improvement is available over 9 mm equipment currently in stock for a secondary firearm. Special units, of course, are often free to use whatever they feel best suits their purposes and have designated funding to deal with that.

Since American law enforcement agencies are not bound by these constraints, most have chosen the .40 S&W roundFact|date=August 2008 (typically replacing their existing sidearms chambered for the 9x19mm Parabellum) for its excellent ammunition capacities, accuracy, and superior ballistic performance.

Case failure reports

The .40 S&W has been noted in a number of cartridge case failures, particularly in Glock pistols due to the relatively large area of unsupported case head in those barrels, given its high working pressure [cite web |url=http://www.thegunzone.com/glock/kb-notes.html |title=.40 S&W Case Failures in Glocks |accessdate=2007-09-25 ] . 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.

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. [cite web |url=http://www.leverguns.com/articles/saami_pressures.htm |title=SAAMI Pressures |accessdate=2007-09-25 ] 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. [cite web |url=http://accuratepowder.com/Safety.htm |title=Safety |publisher=Accurate Arms]

ynonyms

*.40
*.40 S&W
*.40 Liberty (promoted by L. Neil Smith as part of a boycott of Smith and Wesson for making an agreement with the U.S. government under President Bill Clinton. [ [http://www.thefiringline.com/forums/archive/index.php?t-5040.html 40S&W Name Change 40 Liberty+++ [Archive - TheFiringLine Forums ] ] [ [http://www.lneilsmith.org/smithandwessonmustdie.html Smith & Wesson Must Die, by L. Neil Smith ] ] [ [http://www.jpfo.org/alerts/alert20000406.htm Smith & Wesson Must Die ] ]
*.40 Short & Weak (a derogatory comparison to the parent 10 mm Auto cartridge)

ee also

*List of firearms
*List of handgun cartridges
*List of rifle cartridges
*10 mm caliber
*Hydrostatic shock

References

External links

* [http://www.hodgdon.com/data/pistol/40sw.php Ballistics concerning .40 S&W from Hodgdon Powder Co.]
* [http://data.hodgdon.com/cartridge_load.asp Hodgdon/IMR/Winchester's Online Reloading Center]
* [http://www.realguns.com/loads/40sw.htm Reloading Tables with MV, ME & Group Sizes (no pressures)]
* [http://home.columbus.rr.com/jmaass/documents/hl40sw.pdf IPSC Competition Reloading Guide]
* [http://www.handloads.com/loaddata/default.asp?Caliber=40%20SqqqW&Weight=All&type=Handgun&Order=Powder&Source= Reloading Data from HandLoads Website]
* [http://www.firearmstactical.com/ammo_data/40s&w.htm Firearms Tactical Institute Ammunition Performance Data]
* [http://www.brassfetcher.com/40%20S&W.html Ballistic Gel Testing Results]
* [http://www.firearmstactical.com/pdf/fbi-hwfe.pdf FBI: Handgun Wounding Factors & Effectiveness]
* [http://stoppingpower.info/index.php?title=.40 .40 S&W Shooting Videos]