The .357 Smith & Wesson Magnum, .357 S&W Magnum, .357 Magnum, or 9×33mmR (as it is known in unofficial metric designation) is a

smokeless powder Finnish smokeless powder Smokeless powder is a type of propellant used in firearms and artillery that produces less smoke and less fouling when fired compared to black powder. Because of their similar use, both the original black powder formula ...

cartridge with a bullet diameter. It was created by

Elmer Keith Elmer Merrifield Keith (March 8, 1899 – February 14, 1984) was an American rancher, firearms enthusiast, and author. Keith was instrumental in the development of the first magnum revolver cartridge, the .357 Magnum (1935), as well as the la ...

, Phillip B. Sharpe, and Douglas B. Wesson of

firearm A firearm is any type of gun that uses an explosive charge and is designed to be readily carried and operated by an individual. The term is legally defined further in different countries (see legal definitions). The first firearms originate ...

manufacturers

Smith & Wesson Smith & Wesson Brands, Inc. (S&W) is an American Firearms manufacturer, firearm manufacturer headquartered in Maryville, Tennessee, United States. Smith & Wesson was founded by Horace Smith (inventor), Horace Smith and Daniel B. Wesson as the ...

and

Winchester Winchester (, ) is a City status in the United Kingdom, cathedral city in Hampshire, England. The city lies at the heart of the wider City of Winchester, a local government Districts of England, district, at the western end of the South Downs N ...

. The .357 Magnum cartridge is notable for its highly effective

terminal ballistics Terminal ballistics is a sub-field of ballistics concerned with the behavior and effects of a projectile when it hits and transfers its energy to a target. This field is usually cited in forensic ballistics. Bullet design (as well as the veloci ...

. The .357 Magnum cartridge is based upon Smith & Wesson's earlier .38 Special cartridge. It was introduced in 1935, and its use has since become widespread.

Design

The .357 Magnum was collaboratively developed over a period in the early to mid-1930s by a group of individuals as a direct response to Colt's .38 Super Automatic. At the time, the .38 Super was the only American pistol cartridge capable of defeating automobile cover and the early

ballistic vest A bulletproof vest, also known as a ballistic vest or bullet-resistant vest, is a type of body armor designed to absorb impact and prevent the penetration of firearm projectiles and Fragmentation (weaponry), explosion fragments to the torso. The ...

s that were just beginning to emerge in the

Interwar period In the history of the 20th century, the interwar period, also known as the interbellum (), lasted from 11 November 1918 to 1 September 1939 (20 years, 9 months, 21 days) – from the end of World War I (WWI) to the beginning of World War II ( ...

. Tests at the time revealed that those vests defeated any handgun bullet traveling less than about . Colt's .38 Super Automatic just edged over that velocity and was able to penetrate car doors and vests that bootleggers and gangsters were employing as cover. Though .38 Special and .357 Magnum would seem to be different diameter chamberings, they are in fact identical, as at , they both have the same bullet diameter. The .38 Special nomenclature relates to the previous use of heeled bullets (such as the .38 Short Colt and .38 Long Colt), which were the same diameter as the case. The only external dimensional difference between .38 Special and .357 Magnum is the case length; this was done to prevent the accidental loading of .357 Magnum cartridges into .38 Special revolvers not designed for the .357 Magnum's higher chamber pressure. Case volume was not a factor in the increase in case length, as the .38 Special cartridge was originally a black-powder cartridge, while the .357 Magnum was developed using much denser smokeless powder. Much credit for the .357's early development is given to hunter and experimenter

. Keith's early work in loading the .38 Special to increasingly higher pressure levels was made possible by the availability of heavy, target-shooting–oriented

revolver A revolver is a repeating handgun with at least one barrel and a revolving cylinder containing multiple chambers (each holding a single cartridge) for firing. Because most revolver models hold six cartridges before needing to be reloaded, ...

s like the Smith & Wesson .38-44 "Heavy Duty" and "Outdoorsman", .38-caliber revolvers built on .44-caliber frames. The .38-44 HV load used the .38-Special cartridge loaded to a much higher velocity than standard .38-Special ammunition. The .38-44 revolvers were made by using a .44 Special size gun with the barrel bored to accept .357-caliber bullets (the true bullet diameter of the .38 Special) and the cylinder bored to accept cartridges (where the name "38 Special" originated). Since the frame, cylinder, and barrel were much stronger than the standard .38 Special components, it was capable of withstanding much higher pressures. The .38-44 HV round, while no longer available, was in most cases the equal of the later .357 Magnum, which works at more than double the pressure of standard .38 Special. The .357 Magnum addresses safety issues posed by earlier cartridges. Lengthening the cartridge by approximately prevents the high-pressure .357 cartridge from chambering (fitting) in a firearm designed for the shorter, lower-pressure .38 Special. Elmer Keith contributed the Keith-style bullet, which increased the mass of bullet located outside the cartridge case, while leaving more room inside the case for powder. The Keith bullet employed a large, flat meplat for rapid energy transfer to improve wounding capacity. Because this bullet design does not deform like a hollow point, it achieves greater penetration. These characteristics of the Keith bullet make it suitable both for

hunting Hunting is the Human activity, human practice of seeking, pursuing, capturing, and killing wildlife or feral animals. The most common reasons for humans to hunt are to obtain the animal's body for meat and useful animal products (fur/hide (sk ...

and

target shooting Shooting sports is a group of competitive and recreational sporting activities involving proficiency tests of accuracy, precision and speed in shooting — the art of using ranged weapons, mainly small arms (firearms and airguns, in forms such ...

. To reassert itself as the leading law-enforcement

armament A weapon, arm, or armament is any implement or device that is used to deter, threaten, inflict physical damage, harm, or kill. Weapons are used to increase the efficacy and efficiency of activities such as hunting, crime (e.g., murder), law e ...

provider, Smith & Wesson developed the .357 Magnum, with Douglas B. Wesson (grandson of co-founder Daniel B. Wesson) leading the effort within Smith & Wesson, along with considerable technical assistance from Phillip B. Sharpe, a member of the technical division staff of the

National Rifle Association of America The National Rifle Association of America (NRA) is a gun rights advocacy group based in the United States. Founded in 1871 to advance rifle marksmanship, the modern NRA has become a prominent Gun politics in the United States, gun rights ...

. The new round was developed from Smith & Wesson's existing .38 Special round. It used a different powder load, and ultimately the case was extended by . The case extension was more a matter of safety than of necessity. Because the .38 Special and the early experimental .357 Magnum cartridges loaded by Keith were identical in physical attributes, it was possible to load an experimental .357 Magnum cartridge into a .38 Special revolver, with potentially disastrous results. To address this, Smith & Wesson slightly extended the case, which made it impossible to chamber the Magnum-power round in a gun not designed for the additional pressure. The choice of bullet for the .357 Magnum cartridge varied during its development. During the development at Smith & Wesson, the original Keith bullet was modified slightly, to the form of the Sharpe bullet, which itself had been based upon the Keith bullet, but which had 5/6 of the bearing surface of the Keith bullet, Keith bullets typically being made oversized and sized down. Winchester, however, upon experimenting further during the cartridge development, modified the Sharpe bullet shape slightly while keeping its overall contour. The final choice of bullet was thus based upon both the earlier bullet designs, while differing slightly from each.

Dimensions

The .357 Magnum has 1.66

milliliter The litre (Commonwealth English, Commonwealth spelling) or liter (American English, American spelling) (SI symbols L and l, other symbol used: ℓ) is a metric units, metric unit of volume. It is equal to 1 cubic decimetre (dm3), 1000 cubic c ...

(26.2

grain A grain is a small, hard, dry fruit (caryopsis) – with or without an attached husk, hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and ...

) cartridge case capacity.

.357 Magnum maximum C.I.P. cartridge dimensions. All sizes in

millimeter 330px, Different lengths as in respect of the electromagnetic spectrum, measured by the metre and its derived scales. The microwave is between 1 metre to 1 millimetre. The millimetre (American and British English spelling differences#-re, -er, i ...

s (mm) The cartridge headspaces on the rim of the case. The common

rifling Rifling is the term for helical grooves machined into the internal surface of a firearms's barrel for imparting a spin to a projectile to improve its aerodynamic stability and accuracy. It is also the term (as a verb) for creating such groov ...

twist rate Rifling is the term for helical grooves machined into the internal surface of a firearms's barrel for imparting a spin to a projectile to improve its aerodynamic stability and accuracy. It is also the term (as a verb) for creating such groov ...

for this cartridge is 476 mm (1 in 18.74 in), six grooves, ø lands = 8.79 mm, ø grooves = 9.02 mm, land width = 2.69 mm and the primer type is small pistol magnum. According to the C.I.P. rulings, the .357 Magnum cartridge case can handle up to P_max piezo pressure. In C.I.P.-regulated countries, every pistol cartridge combination has to be proofed at 130% of this maximum C.I.P. pressure to certify for sale to consumers. This means that .357 Magnum chambered arms in C.I.P.-regulated countries are currently proof tested at PE piezo pressure.

Performance

This cartridge is regarded by many as an excellent

metallic silhouette Metallic silhouette shooting is a group of target shooting disciplines that involves shooting at steel targets representing game animals at varying distances, seeking to knock the metal target over. Metallic silhouette is shot with large bore rif ...

, and

self-defense Self-defense (self-defence primarily in Commonwealth English) is a countermeasure that involves defending the health and well-being of oneself from harm. The use of the right of self-defense as a legal justification for the use of Force (law), ...

round. With proper loadings it can also be effective against large or dangerous

game A game is a structured type of play usually undertaken for entertainment or fun, and sometimes used as an educational tool. Many games are also considered to be work (such as professional players of spectator sports or video games) or art ...

, such as

bear Bears are carnivoran mammals of the family (biology), family Ursidae (). They are classified as caniforms, or doglike carnivorans. Although only eight species of bears are extant, they are widespread, appearing in a wide variety of habitats ...

and

ungulate Ungulates ( ) are members of the diverse clade Euungulata ("true ungulates"), which primarily consists of large mammals with Hoof, hooves. Once part of the clade "Ungulata" along with the clade Paenungulata, "Ungulata" has since been determined ...

s. The .357 Magnum has less energy than the larger magnum revolver loadings but is smaller in diameter with high velocity allowing for excellent penetration properties. It is a fine small- and medium-game round and is sufficient to hunt

deer A deer (: deer) or true deer is a hoofed ruminant ungulate of the family Cervidae (informally the deer family). Cervidae is divided into subfamilies Cervinae (which includes, among others, muntjac, elk (wapiti), red deer, and fallow deer) ...

at reasonable ranges if suitable loadings are used by a competent marksman. For further comparison, the .357 Magnum has a higher velocity at than its parent case (.38 Special) has at the muzzle. The .357 Magnum's effectiveness on game is similar to that of the .45 Colt, but with a much flatter trajectory due to its higher velocity. It has been used with success for self-defense, plinking, hunting, or target shooting."The Versatile .357 Magnum" by Chuck Hawks (subscription required)
/ref> The original .357 Magnum load was a bullet with an advertised muzzle velocity of and muzzle energy of . (Muzzle velocity was taken using a large frame revolver with a fairly long barrel of ) Most of today's

SAAMI The Sporting Arms and Ammunition Manufacturers' Institute (SAAMI, pronounced "Sammy") is an association of American manufacturers of firearms, ammunition, and components. SAAMI is an accredited standards developer that publishes several A ...

conform loads are fairly mild when compared to the original mid-1930s load. Today's C.I.P. conform loads can duplicate the original mid-1930s load. When using a revolver with a shorter barrel, today's C.I.P. conform maximum loads with a bullet can reach a muzzle velocity of . For a handgun cartridge, the

bolt thrust Bolt thrust or breech pressure is a term used in internal ballistics and firearms (whether small arms or artillery) that describes the amount of rearward force exerted by the propellant gases on the Bolt (firearms), bolt or Breechblock, breech of a ...

is considerable at C.I.P. conform maximum loads and an important factor in weapons design. The greater the bolt thrust, the stronger the locking mechanism has to be to withstand it. Revolvers chambered in .357 Magnum have the significant advantage of also being able to chamber and fire the shorter and less-powerful .38 Special cartridge. Compared to the .357 Magnum, .38 Special is also lower in cost,

recoil Recoil (often called knockback, kickback or simply kick) is the rearward thrust generated when a gun is being discharged. In technical terms, the recoil is a result of conservation of momentum, for according to Newton's third law the force requ ...

, noise, and

muzzle flash Muzzle flash is the light — both visible and infrared — created by a muzzle blast, which is caused by the sudden release and expansion of high-temperature, high-pressure gases from the muzzle of a firearm during shooting. Both the blast ...

. The ability to also fire the .38 Special makes .357 revolvers ideal for novice shooters who are not yet used to firing full-power .357 magnum loads but do not want the expense of buying a second lower-powered gun to train with. However, .38 Special ammunition should not generally be used with any .357 magnum ''semiautomatic'' handgun or rifle, since such firearms require the larger recoil produced by firing a .357 Magnum round to cycle properly. The .357 Magnum has also become popular as a "dual-use" cartridge in short, light rifles like the

American Old West The American frontier, also known as the Old West, and popularly known as the Wild West, encompasses the geography, history, folklore, and culture associated with the forward wave of American expansion in mainland North America that bega ...

lever-action The toggle-link action used in the iconic Winchester Model 1873 rifle, one of the most famous lever-action firearms Picture showing a Volcanic Pistol A lever action is a type of action for repeating firearms that uses a manually operated cocki ...

s. In a rifle, the bullet will exit the barrel at about , making it far more versatile than the .30 Carbine or the .32-20 Winchester. In the 1930s it was found to be very effective against steel car doors and ballistic vests, and metal-penetrating rounds were once popular in the United States among

highway patrol A highway patrol is a police unit, detail, or law enforcement agency created primarily for the purpose of overseeing and enforcing traffic safety compliance on roads and highways within a jurisdiction. They are also referred to in many countri ...

state police State police, provincial police or regional police are a type of sub-national territorial police force found in nations organized as federations, typically in North America, South Asia, and Oceania. These forces typically have jurisdiction o ...

, sheriffs and other police agencies. The .357 magnum revolver has been largely replaced by modern, high-capacity

semi-automatic pistol A semi-automatic pistol (also called a self-loading pistol, autopistol, or autoloading pistol) is a repeating firearm, repeating handgun that automatically ejects and loads cartridge (firearms), cartridges in its chamber (firearms), chamber afte ...

s for police use, but it is still very popular for backup gun use and among outdoorsmen,

security guard A security guard (also known as a security inspector, security officer, factory guard, or protective agent) is a person employed by a government or private party to protect the employing party's assets (property, people, equipment, money, etc.) ...

s, and civilians for hunting, metallic silhouette, target shooting, and self-defense. The

9mm Winchester Magnum The 9mm Winchester Magnum, which is also known as the 9×29mm, is a centerfire handgun cartridge developed by Winchester Winchester (, ) is a City status in the United Kingdom, cathedral city in Hampshire, England. The city lies at the hear ...

, which is also known as the 9×29mm, was developed to duplicate the performance of the .357 Magnum in a semi-automatic pistol, as was the .357 SIG cartridge. Some common performance parameters are shown in the table below for several .357 Magnum loads. Bullet weights ranging from are common. The jacketed hollow point loads are popular for self-defense, whereas the heavier loads are commonly used for hunting. Loads are available with energies typically from 400 and 800 foot-pounds force (542 and 1,085 joules) and can be selected for various applications based on desired use 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)

Comparison

In terms of accuracy, the .357 Magnum has at least the same potential for precision shooting as the benchmark .38 Special wadcutter round—indeed, a good .357 Magnum revolver will shoot .38 Special wadcutter ammunition with good results. It is this accuracy and power, and the versatility of also being capable of using less-expensive, milder .38 Special ammunition, that makes a .357 Magnum revolver an excellent gun for many different disciplines, from precision shooting to long-range falling-plate events. It is an excellent round for those considering

handloading Handloading, or reloading, is the practice of making firearm cartridges by manually assembling the individual components ( metallic/ polymer case, primer, propellant and projectile), rather than purchasing mass-assembled, factory-loaded com ...

ammunition, as it is economical and consistently performs well. The .357 Magnum was developed from the earlier .38 Special. This was possible because the .38 Special was introduced in 1898 and originally designed to use

black powder Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, charcoal (which is mostly carbon), and potassium nitrate, potassium ni ...

, which requires two-to-five times as much powder by volume to produce the same velocity with the same bullet as does the much more efficient

. Thus, the .38 Special has a relatively large case capacity, and for lower pressures ( P_max piezo pressure). The

9×19mm Parabellum The 9×19mm Parabellum (also known as 9mm Luger, 9mm NATO or simply 9mm) is a Rim (firearms)#Rimless, rimless, Centerfire ammunition, centerfire, tapered cartridge (firearms), firearms cartridge. Originally designed by Austrian firearm designer ...

was introduced in 1902 and was originally designed to use smokeless powder, and for higher pressures ( P_max piezo pressure). It therefore produces considerably more energy than the .38, despite its case having less than half the powder capacity. Many .38 Special loads use the same powders, in similar charge weights, but because the case is so much larger, light-target loads with fast-burning powders may only fill the case perhaps 1/8 full. Filling the case with slower-burning powders produces much more power, but also much more pressure; far too much pressure for older, smaller-frame revolvers chambered in .38 Special. It was to accommodate these high-pressure, high-power loads that the longer .357 Magnum, together with the stronger revolvers designed to handle it, were developed. The .357 SIG, developed in 1994, was named "357" to highlight its intended purpose: to duplicate the performance of .357 Magnum loads fired from revolvers, in a cartridge designed to be used in a semi-automatic pistol.

References

Notes

External links