Winchester Super Short Magnum, or WSSM is a line 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), a ...

s introduced by the U.S. Repeating Arms Company (''Winchester Inc''). It is a further development of the

Winchester Short Magnum Winchester Short Magnum, or WSM, refers to a family of rebated rim bottlenecked centerfire short magnum cartridges developed in the early 2000s by the U.S. Repeating Arms Company, the maker of Winchester rifles and one of the oldest firearms man ...

concept utilizing smaller bullets, but of a still higher velocity.

History

Winchester and Browning partnered to create a new shorter version of the popular WSM (Winchester Short magnum) case. The new "super short" case was to be based on design principles currently proving successful in

benchrest Benchrest shooting is a shooting sport discipline in which accuracy and precision, high-precision rifles are rested on a table (furniture), table or countertop, bench — rather than being carried in the shooter's hands — while shooting at sho ...

competition, such as the 6 mm PPC and

6 mm BR Remington 6 (six) is the natural number following 5 and preceding 7. It is a composite number and the smallest perfect number. In mathematics Six is the smallest positive integer which is neither a square number nor a prime number; it is the second smalles ...

. In 2003 the first cartridges of this design, the

.223 The .223 Remington (designated as the 223 Remington by the SAAMI and 223 Rem by the CIP) is a rimless, bottlenecked rifle cartridge. It was developed in 1957 by Remington Arms and Fairchild Industries for the U.S. Continental Army Command ...

and

.243 The .243 Winchester (6×52mm) is a popular sporting rifle cartridge. Developed as a versatile short action cartridge to hunt both medium game and small game alike, it "took whitetail hunting by storm"Ron Spomer.Whitetail Deer Cartridge Shoot-Out ...

Winchester Super Short Magnums (WSSM), were introduced. The

.25 WSSM The .25 Winchester Super Short Magnum is a third member of the Winchester Super Short Magnum (WSSM) cartridge family created by Winchester and Browning. It is the largest caliber of the WSSM line (excluding wildcats) and is the most capable of ...

was added to the family in 2004. None of the cartridges has managed to capture any large market share. This is likely due in part to the fact that all three cartridges have similar performance to existing popular cartridges. In addition, the .223 and .243 versions early on attained a reputation for quickly eroding the rifling in barrels. Concerns about short barrel life are a common problem for high-velocity cartridges, making the WSSM rounds no different than other high-velocity cartridges. To help mitigate the problem, Browning currently uses chrome-lined barrels on all of their guns chambered for .223 WSSM.

Advantages

There are basic advantages inherent to the Short Magnum concept. The idea is that the short, fat powder column gives a more uniform load density and ignition rate and therefore a more consistent burn. This in turn should translate into improved accuracy and potentially moderate recoil due to more efficient use of propellants. Another advantage is the action size. For example, if we compare the .25 WSSM to the

.25-06 Remington Considered by many as the most balanced of the "quarter bores" for hunting medium-sized game, the .25-06 Remington remained in obscurity as a wildcat cartridge for nearly half a century before being standardized by Remington in 1969. Its design ...

, we find that the .25-06 requires a .30-06 length action, commonly called a ''standard'' or ''long action''. The .25 WSSM case which is almost a full inch shorter, can make use of an existing short action such as used by the 5.56 NATO and

.223 Remington The .223 Remington (designated as the 223 Remington by the SAAMI and 223 Rem by the CIP) is a rimless, bottlenecked rifle cartridge. It was developed in 1957 by Remington Arms and Fairchild Industries for the U.S. Continental Army Command ...

family of cartridges. Some manufacturers have even created extra short actions to accommodate newer short rounds. The intrinsic accuracy benefits of a short, stiffer action over a long action are well-established principles of rifle design. The resulting rifle is smaller, lighter, more compact, and quicker handling as well.

Disadvantages

The relatively large diameter cases result in reduced magazine capacity and reliability along with a thinner bolt face, meaning it can break easily especially under the higher pressure of the cartridges.

Cartridge Family

The cartridges in this family are, in order of development: Like any new case introduced, wildcatters like to see what they can do to make new cartridges. Two of the more notable children or offshoots of this case are the .325 Corbin, which is essentially an 8 mm WSSM, and the .22/40 SMc, which is essentially the .223 WSSM with an elliptical shoulder. A

wildcat cartridge A wildcat cartridge, often shortened to wildcat, is a custom cartridge for which ammunition and/or firearms are not mass-produced. These cartridges are often created in order to optimize a certain performance characteristic (such as the power, s ...

based on the .25 WSSM, called the .358 WSSM or .358 BFG, has similar performance to the standard .358 Winchester and .35 Whelen.
BFG Design Additionally, Olympic arms created the .300 OSSM, which is a 25 WSSM necked up to .308” giving performance between .30-06 Springfield, 30-06 and

.300 Winchester Magnum The .300 Winchester Magnum (also known as .300 Win Mag or .300 WM) (7.62×67mmB, 7.62x66BR) is a belted, bottlenecked magnum rifle cartridge that was introduced by the Winchester Repeating Arms Company in 1963. The .300 Winchester Magnum is a m ...

References

;Notes *
WSM and WSSM ballistic Comparison Chart
from Browning {{refend

External links