Winchester Short Magnum, or WSM, refers to a family of

rebated rim A rim is an external flange that is machined, cast, molded, stamped, or pressed around the bottom of a firearms cartridge. Thus, rimmed cartridges are sometimes called "flanged" cartridges. Almost all cartridges feature an extractor or headspacing ...

bottlenecked

centerfire Two rounds of .357 Magnum, a centerfire cartridge; notice the circular primer in the center A centerfire cartridge is a firearm metallic cartridge whose primer is located at the center of the base of its casing (i.e. "case head"). Unlike rim ...

short magnum

cartridge Cartridge may refer to: Objects * Cartridge (firearms), a type of modern ammunition * ROM cartridge, a removable component in an electronic device * Cartridge (respirator), a type of filter used in respirators Other uses * Cartridge (surname) Ca ...

s developed in the early 2000s by the U.S. Repeating Arms Company, the maker of

Winchester rifle Winchester rifle is a comprehensive term describing a series of lever action repeating rifles manufactured by the Winchester Repeating Arms Company. Developed from the 1860 Henry rifle, Winchester rifles were among the earliest repeaters. The Mo ...

s and one of the oldest firearms manufacturers in the United States. All of the WSM cartridges are inspired on the

.404 Jeffery The .404 Jeffery is a rifle cartridge designed for hunting large, dangerous game animals, such as the " Big Five" (elephant, rhino, cape buffalo, lion and leopard) of Africa. The cartridge is standardized by the C.I.P. and is also known as .404 ...

non-belted magnum cartridge which is shortened to fit a short

rifle A rifle is a long-barreled firearm designed for accurate shooting, with a barrel that has a helical pattern of grooves ( rifling) cut into the bore wall. In keeping with their focus on accuracy, rifles are typically designed to be held with ...

action (such as a

.308 Winchester The .308 Winchester is a smokeless powder rimless bottlenecked rifle cartridge widely used for hunting, target shooting, police, military, and personal protection applications globally. It is similar but not identical to the 7.62×51mm NATO ...

). It was developed by Rick Jamison in 1997-1998 as proven in a 2005 lawsuit Jamison vs. Olin Corporation-Winchester division. Jamison was given 7 patents on the cartridge design. U.S. Repeating Arms Company used the same concept and the same base case in creating its even shorter

Winchester Super Short Magnum Winchester Super Short Magnum, or WSSM is a line of rebated rim bottlenecked centerfire short magnum cartridges introduced by the U.S. Repeating Arms Company (''Winchester Inc''). It is a further development of the Winchester Short Magnum concept ...

cartridges, three of which were introduced in 2003 and 2004.

Influences

7.82 Lazzeroni Patriot

The WSM family was inspired partially by a family of proprietary short magnum cartridges developed in late 1997,John Lazzeroni comments on rec.guns
/ref> by John Lazzeroni, derived from a previous line of magnum cartridges he had created. The first Lazzeroni short magnum, the 7.82 Lazzeroni Patriot, was designed to operate in a short-action rifle, instead of requiring a long action. The U.S. Repeating Arms Company was the first major manufacturer to commercialize Lazzeroni's concept, followed shortly thereafter by

Remington Remington may refer to: Organizations * Remington Arms, American firearms manufacturer * Remington Rand, American computer manufacturer * Remington Products, American manufacturer of shavers and haircare products * Remington College, American c ...

with their "Short Action Ultra Mag" line.

6 mm Benchrest

Another influence was a series of 6 mm cartridges developed for bench-rest target shooting competitions in the 1970s. The idea behind these cartridges was that a short, fat cartridge would be more "efficient" than the traditional long, narrow cartridge, as more of the powder column would be in the immediate vicinity of the primer as it detonated. In turn, this would mean that a cartridge of this type would be able to propel a bullet at speeds comparable to those of "magnum" cartridges of the same caliber using significantly less powder.

Dimensions

The dimensions of the basic case are: * Rim diameter (at base): .535 in. (13.59 mm) * Outside diameter (at base): .555 in. (14.10 mm) * Inside diameter (of case): .538 in. (13.67 mm) * Maximum case length: 2.10 in. (53.34 mm) The WSM family of cartridges are

Delta L problem The delta L problem (ΔL problem) refers to certain firearm chambers and the incompatibility of some ammunition made for that chamber. ΔL is a Commission Internationale Permanente (C.I.P.) geometric dimensioning and tolerancing definition for c ...

cartridges, meaning they can present unexpected chambering and/or feeding problems.

Variants

The 300 WSM was the first of the new class of short magnums to see wide use. All of the WSM cartridges released to date have proven popular for thin-skinned game up to the size of

elk The elk (''Cervus canadensis''), also known as the wapiti, is one of the largest species within the deer family, Cervidae, and one of the largest terrestrial mammals in its native range of North America and Central and East Asia. The common ...

and African plains game, the .325 WSM being an excellent cartridge for elk, bison and similar big game. The cartridges in this family are, in order of development: {, class="wikitable" style="text-align:center" !Name !Year of development !Bullet diameter , - ,

300 WSM 3 (three) is a number, numeral and digit. It is the natural number following 2 and preceding 4, and is the smallest odd prime number and the only prime preceding a square number. It has religious or cultural significance in many societie ...

, , 2001 , , .308 in. (7.823 mm) , - , 7 mm WSM , , 2002 , , .284 in. (7.214 mm) , - ,

270 WSM 7 (seven) is the natural number following 6 and preceding 8. It is the only prime number preceding a cube (algebra), cube. As an early prime number in the series of positive integers, the number seven has greatly symbolic associations in religion ...

, , 2002 , , .277 in. (7.036 mm) , - ,

325 WSM 3 (three) is a number, numeral and digit. It is the natural number following 2 and preceding 4, and is the smallest odd prime number and the only prime preceding a square number. It has religious or cultural significance in many societie ...

, , 2005 , , .323 in. (8.204 mm) , -

References