Winchester Short Magnum, or
WSM, refers to a "family" of cartridges developed in the early 2000s by the
U.S. Repeating Arms CompanyThe U.S. Repeating Arms Company. Inc. is the current avatar of the Winchester Repeating Arms Company, famous for making Winchester rifles....
, the maker of
Winchester rifleThe term Winchester Rifle is frequently used to describe any of the lever-action rifles manufactured in the United States by the Winchester Repeating Arms Company, although the name is usually more specifically used in reference to the Winchester Model 1873 or the Winchester Model 1894...
s and one of the oldest firearms manufacturers in the United States. All of the WSM cartridges are based on the
.404 JefferyThe .404 Jeffery is a large caliber, rimless cartridge designed for large, dangerous game, such as the big five of Africa. Other names for this cartridge include .404 Jeffery Rimless, .404 Rimless Nitro Express, and 10.75 x 73 mm...
non-belted magnum cartridge which is shortened to fit a short
rifleA rifle is a firearm designed to be fired from the shoulder, with a barrel that has a helical groove or pattern of grooves cut into the barrel walls. The raised areas of the rifling are called "lands," which make contact with the projectile , imparting spin around an axis corresponding to the...
action (such as a
.308 WinchesterThe .308 Winchester is a rifle round and is the commercial version of the military 7.62x51mm NATO centerfire cartridge. The .308 Winchester was introduced in 1952, two years prior to the NATO adoption of the 7.62x51mm NATO T65. Winchester branded the cartridge and introduced it to the commercial...
).
USRAC used the same concept and the same base case in creating its even shorter
Winchester Super Short MagnumWinchester Super Short Magnum, or WSSM is a line of cartridges introduced by the U.S. Repeating Arms Company . It is a further development of the Winchester Short Magnum concept utilizing smaller bullets, but still of a high velocity....
cartridges, three of which were introduced in 2003 and 2004.
The WSM family was inspired partially by a family of proprietary short magnum cartridges developed by John Lazzeroni, derived from a previous line of magnum cartridges he had created.
Winchester Short Magnum, or
WSM, refers to a "family" of cartridges developed in the early 2000s by the
U.S. Repeating Arms CompanyThe U.S. Repeating Arms Company. Inc. is the current avatar of the Winchester Repeating Arms Company, famous for making Winchester rifles....
, the maker of
Winchester rifleThe term Winchester Rifle is frequently used to describe any of the lever-action rifles manufactured in the United States by the Winchester Repeating Arms Company, although the name is usually more specifically used in reference to the Winchester Model 1873 or the Winchester Model 1894...
s and one of the oldest firearms manufacturers in the United States. All of the WSM cartridges are based on the
.404 JefferyThe .404 Jeffery is a large caliber, rimless cartridge designed for large, dangerous game, such as the big five of Africa. Other names for this cartridge include .404 Jeffery Rimless, .404 Rimless Nitro Express, and 10.75 x 73 mm...
non-belted magnum cartridge which is shortened to fit a short
rifleA rifle is a firearm designed to be fired from the shoulder, with a barrel that has a helical groove or pattern of grooves cut into the barrel walls. The raised areas of the rifling are called "lands," which make contact with the projectile , imparting spin around an axis corresponding to the...
action (such as a
.308 WinchesterThe .308 Winchester is a rifle round and is the commercial version of the military 7.62x51mm NATO centerfire cartridge. The .308 Winchester was introduced in 1952, two years prior to the NATO adoption of the 7.62x51mm NATO T65. Winchester branded the cartridge and introduced it to the commercial...
).
USRAC used the same concept and the same base case in creating its even shorter
Winchester Super Short MagnumWinchester Super Short Magnum, or WSSM is a line of cartridges introduced by the U.S. Repeating Arms Company . It is a further development of the Winchester Short Magnum concept utilizing smaller bullets, but still of a high velocity....
cartridges, three of which were introduced in 2003 and 2004.
7.21 Lazzeroni
The WSM family was inspired partially by a family of proprietary short magnum cartridges developed by John Lazzeroni, derived from a previous line of magnum cartridges he had created. Lazzeroni's short magnums (
7.21 LazzeroniLazzeroni cartridges are a range of extremely powerful proprietary magnum sporting rifle cartridges developed and manufactured since the early 1990s by US hunting enthusiast John Lazzeroni...
Fireball and Tomahawk) were 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
RemingtonRemington Arms is a major American manufacturer of rifles, shotguns, other firearms, revolvers and ammunition. They also license the Remington name to hunting apparel, Arctic Cat ATV's, and other hunting and shooting products manufactured by other companies. It was founded in 1816 by Eliphalet...
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 problemThe delta L problem is a condition that occurs regarding certain firearms chambers and their practical incompatibility with ammunition made for the corresponding chambering....
cartridges, meaning they can present unexpected chambering and/or feeding problems. The
Delta L problemThe delta L problem is a condition that occurs regarding certain firearms chambers and their practical incompatibility with ammunition made for the corresponding chambering....
article explains this problem in more detail.
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-Various species of deer:** European Elk , also known as Moose** North American Elk , also known as Wapiti** Indian Elk , also known as Sambar...
and African plains game.
The cartridges in this family are, in order of development:
| Name |
Year of development |
Bullet diameter |
| 300 WSM |
2001 |
.308 in. (7.823 mm) |
7 mm WSMThe 7mm WSM is a centrefire cartridge developed in partnership with Browning Arms Company and Winchester ammunition, making its debut and introduced to the shooting public in 2001. The 7mm WSM is based on the .300 WSM case necked down to handle .284" bullets...
|
2002 |
.284 in. (7.214 mm) |
| 270 WSM The .270 Winchester Short Magnum or .270 WSM is a short, unbelted, magnum Cartridge created by necking down the .300 Winchester Short Magnum and fitting it with a .270 caliber bullet.-Overview:...
|
2002 |
.277 in. (7.036 mm) |
| 325 WSM |
2005 |
.323 in. (8.204 mm) |
The .325 WSM is an excellent cartridge for elk, bison and similar big game. The .325 WSM has proven in actual hunting to have tremendous shock power and has resulted in one shot stops of Roosevelt Elk, bison and bear.