The 243 Winchester Super Short Magnum or 243 WSSM is a

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 ...

cartridge introduced in 2003. It uses a .300 WSM (

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 m ...

) case shortened and necked down to accept a .243in/6mm diameter bullet, and is a high velocity round based on

ballistics Ballistics is the field of mechanics concerned with the launching, flight behaviour and impact effects of projectiles, especially ranged weapon munitions such as bullets, unguided bombs, rockets or the like; the science or art of designing ...

design philosophies that are intended to produce a high level of efficiency. The correct name for the cartridge, as listed by the Sporting Arms and Ammunition Manufacturers' Institute (SAAMI), is 243 WSSM, without a decimal point. Winchester has discontinued the manufacture of 243 WSSM ammunition. As of the first half of 2016, Winchester/Olin did manufacture and release for sale some WSSM ammunition. The product is only manufactured periodically, often at inconsistent intervals.

Design

The 243 WSSM is an addition to the

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 con ...

(WSSM) family of cartridges, which also include the .223 WSSM and the .25 WSSM, and the idea behind the 243 WSSM was to develop a compact, higher velocity version of the well-established and internationally popular .243 Winchester unveiled by Winchester in 1955. The 243 WSSM was first introduced in 2003. The 243 WSSM's case is unusually short and fat in profile, contrasting markedly with most other rifle cartridges, and is intended to take advantage of what ballisticians have shown is the more uniform and efficient

burning Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combust ...

of propellant powder when it is held in a short, fat stack by the cartridge case.

Performance

In their ballistics tables,

Winchester Winchester is a cathedral city in Hampshire, England. The city lies at the heart of the wider City of Winchester, a local government district, at the western end of the South Downs National Park, on the River Itchen. It is south-west of Lo ...

list a very high muzzle velocity of with a projectile for this cartridge. Based on Hodgdon reloading data typical velocities should range from approximately with a bullet to approximately with a bullet. The percentage gain in performance over the older .243 Winchester is around 10% or less. This cartridge is usually used for small game such as varminting, and used for animals as large as

deer Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the reindeer ...

Advantages

Compared to other factory 6mm sporting cartridges the 243 WSSM is capable of functioning in the

AR-15 An AR-15-style rifle is any lightweight semi-automatic rifle based on the Colt AR-15 design. The original ArmaLite AR-15 is a scaled-down derivative of Eugene Stoner's ArmaLite AR-10 design. The then Fairchild Engine and Airplane Corporatio ...

. Other factory produced 6mm cartridges like the 243 Win and 6mm Rem are both too long for the AR-15 and require the AR-10 platform. The 243 WSSM is shorter than the 243 Win, giving the 243 WSSM the ability to fit in a super-short action rifle. Thus 243 WSSM rifles can be lighter, have stiffer actions and have faster actions to cycle. The 243 WSSM gives generally a 10% increase in velocity over the 243 Win.

References

Cartridge Dimensions
at Steves Pages

External links

243 WSSM – The Long-Awaited 6 mm "Answer"?
By Bill Prudden

by Chuck Hawks
The Experts Agree The WSSMs are Winners!
Browning
The 243 WSSM
at Guns & Ammo
Hunting experiences with the 243 WSSM
243WSSM.com {{DEFAULTSORT:243 Wssm Pistol and rifle cartridges Winchester Super Short Magnum rifle cartridges

Design

Performance

Advantages

See also

References

External links