.40 S&W
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| .40 S&W | ||
|---|---|---|
 .40 S&W compared to other catridges (third from right). |
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| Type | Pistol | |
| Place of origin | United States | |
| Production history | ||
| Designer | Smith & Wesson | |
| Designed | January 17, 1990 | |
| Specifications | ||
| Parent case | 10 mm Auto | |
| Case type | Rimless, straight | |
| Bullet diameter | .40 in (10.16 mm) | |
| Neck diameter | .423 in (10.74 mm) | |
| Base diameter | .424 in (10.77 mm) | |
| Rim diameter | .424 in (10.77 mm) | |
| Rim thickness | .055 in (1.4 mm) | |
| Case length | .850 in (21.59 mm) | |
| Overall length | 1.135 in (28.83 mm) | |
| Primer type | Small pistol | |
| Ballistic performance | ||
| Bullet weight/type | Velocity | Energy |
| 135 gr JHP | 1200 ft/s (~366 m/s) |
432 ft·lbf (~588 J) |
| 155 gr JHP | 1140 ft/s (~348 m/s) |
447 ft·lbf (~608 J) |
| 165 gr JHP | 980 ft/s (~299 m/s) |
352 ft·lbf (~479 J) |
| 180 gr JHP | 1000 ft/s (~305 m/s) |
400 ft·lbf (~544 J) |
| Test barrel length: 4 in Source: Federal Cartridge Co. ballistics page |
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The .40 S&W is a rimless pistol cartridge developed jointly by Winchester and Smith & Wesson, two famous American firearms manufacturers. [1] It uses .400" (10 mm) diameter bullets ranging in weight from 135 to 200 grains and operates at about 33,000 psi pressure.
Contents |
[edit] History
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. The .40 S&W evolved from the 10 mm Auto pistol ammunition which had been adopted by the FBI, but turned out to be too powerful for some of the agents, and exhibited poor accuracy when rapid-firing. The 10 mm Auto gave performance akin to the .41 Magnum pistol round and recoil and muzzle blast, especially in a short barrel, were found to be just too much for many shooters. Essentially it was found that a pistol powerful enough for deer was just not needed for the purpose of defense or law enforcement. The FBI started using a lowered charge version of the 10 mm Auto ammunition, a subsonic load often referred to as the "FBI load" or "10 mm lite." Smith & Wesson redesigned the cartridge to make it shorter while maintaining the performance of the FBI load. They also decided to use a small pistol primer, rather than the large primer used for the 10mm Auto. The .40 S&W cartridge quickly surpassed the 10 mm cartridge in popularity and units sold. With the .40 S&W being shorter than the 10 mm Auto and approximately the same length as the 9 mm Luger cartridge, many existing 9 mm Luger pistols could be adapted by their respective manufacturers to fire the new cartridge.
The case of the original 10 mm Auto had the same head dimensions as the old .30 Remington that was designed in about 1906 for the Remington Model 8 semi-auto deer rifle. The bullet was the same diameter as the old .38-40 dual use rifle/revolver round from the Old West. The .38-40, long obsolete, was known for good stopping power, and the .40 S&W reflects this, in a far more compact package.
In a great irony, Austrian manufacturer Glock beat Smith & Wesson to the dealer shelves with a pistol chambered in .40 S&W in 1990, the Glock 22 and 23, which were announced a week after the 4006.[2] Glock's rapid introduction was aided by its engineering of a pistol chambered in 10 mm Auto only a short time earlier, the Glock 20. The Glock 20 was and still is considered an excellent pistol in 10 mm Auto, but has sold vastly fewer units than the .40 S&W Glocks.
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."[3][4]
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 fitted out 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 1000 feet per second 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.
[edit] Performance
The .40 S&W cartridge has become a huge success in the United States because, while possessing nearly identical accuracy[5], drift and drop, it adds 50% more energy over the 9mm Luger 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.
The energy of the .40 S&W exceeds all standard-pressure and +P 9 mm Luger loadings and many standard-pressure .45 ACP rounds, generating between 350 and 650 foot-pounds (475 and 880 joules) of energy, depending on bullet weight, with mid to high 400's typical. Both the .40 S&W and the 9mm Luger operate at a 35,000 psi SAAMI maximum, compared to a 21,000 psi maximum for .45 ACP[6]. Handloads are capable of producing .40 S&W loads within SAMMI pressure specification that generate in excess of 650 foot-pounds of energy. This is accomplished through the use various types of gun powder with different burn rates to produce more persistently high pressure over longer intervals rather than simply the highest possible peak pressure. Some small ammunition manufacturers offer .40 S&W ammunition near this level of performance as off-the-shelf items.[7]. 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.
The .40 S&W is considered by some the best cartridge for law enforcement use available today, combining superior stopping power when using expanding ammunition and manageable recoil in a package that remains compact, even when using a double-stack magazine. The .40 S&W has an overwhelming share of the U.S. law enforcement market as a result.
Despite the .40 S&W's great popularity amongst American law enforcement and the private sector, it has yet to be adopted by a significant number of military forces worldwide. The mainstay for military use in the western world largely remains the preserve of the 9mm Luger, or for US 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] 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 weak case of the .40 S&W, given its high working pressure,[8] and lack of full chamber support. In particular, 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 typical, but 35,000 SAAMI max) for a large caliber handgun cartridge, significantly more than, say, the .45 ACP.[9] 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 9 x 19 mm 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 is reducing the margin of safety; when exacerbated by out of battery firing (leaving even more case head unexposed) and potentially weakened brass (due to reloading) these factors appear to lead to the higher incidents of chamber failure.
[edit] Synonyms
- .40
- .40 S&W
- .40 Auto
- .40 Short & Wimpy or Short & Weak (a derogatory comparison to the parent 10 mm Auto cartridge)
- .40 Liberty (in the same tradition as "freedom fries," following the boycott of Smith & Wesson in the wake of their agreement with the Clinton Administration)
- 10 mm Kurz
[edit] References
- ^ California Highway Patrol selects .40 S&W Model 4006 as the agency's duty sidearm
- ^ September 2005 Guns Magazine article
- ^ Guns Magazine article using the term "Short and Weak"
- ^ American Handgunner Magazine article using the term "Short and Weak"
- ^ Accuracy of 9mm v.s .40 S&W in Beretta Cougar
- ^ SAAMI pressure specs from Handloads.com
- ^ Double Tap Ammunition
- ^ .40 S&W Case Failures in Glocks
- ^ SAAMI pressure specifications
[edit] See also
[edit] External links
- Ballistics concerning .40 S&W from Hodgdon Powder Co.
- Hodgdon/IMR/Winchester's Online Reloading Center
- Reloading Tables with MV, ME & Group Sizes (no pressures)
- IPSC Competition Reloading Guide
- Reloading Data from HandLoads Website
- Firearms Tactical Institute Ammunition Performance Data
- Ballistic Gel Testing Results
- FBI: Handgun Wounding Factors & Effectiveness
