.243 WSSM
Encyclopedia
The 243 Winchester Super Short Magnum or 243 WSSM is a rifle
cartridge
introduced in 2003. It uses a .300 WSM
(Winchester Short Magnum
) case shortened and necked down to accept a .243in/6mm
diameter bullet, and is a high velocity round based on ballistics
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.
(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'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
of propellant powder when it is held in a short, fat stack by the cartridge case.
Some rifle manufacturers such as Browning
have also taken to chrome-lining their barrels' bores to make them less susceptible to the wear caused by the high levels of bullet friction and very high propellant gas temperatures that occur with WSSM cartridges.
list a very high muzzle velocity of 4060 ft/s (1,237.5 m/s) with a 55 gr projectile for this cartridge. Based on Hodgdon reloading data typical velocities should range from approximately 4000 ft/s (1,219.2 m/s) with a 58 gr bullet to approximately 3000 ft/s (914.4 m/s) with a 100 gr bullet. The percentage gain in performance over the older .243 Winchester is around 10% or less, and it remains to be seen if the market will offer a commercially viable place to two 6 mm sporting cartridges that have such similar performance.
This cartridge is usually used for small game such as varminting, and used for animals as large as deer
.
The 243 WSSM is 3/8 inch shorter than the 243 Win. giving the 243 WSSM the ability to fit an 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.
Rifle
A 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...
cartridge
Cartridge (firearms)
A cartridge, also called a round, packages the bullet, gunpowder and primer into a single metallic case precisely made to fit the firing chamber of a firearm. The primer is a small charge of impact-sensitive chemical that may be located at the center of the case head or at its rim . Electrically...
introduced in 2003. It uses a .300 WSM
.300 WSM
.300 Winchester Short Magnum is a thirty caliber rebated rim bottlenecked centerfire short magnum cartridge that was introduced in 2001 by Winchester. The cartridge overall length is 72.64mm, cartridge case is 53.34mm in length and the bullet diameter is .308 in , which is common to all U.S. .30...
(Winchester Short Magnum
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 manufacturers in the United States...
) case shortened and necked down to accept a .243in/6mm
6 mm caliber
This article lists firearm cartridges which have a bullet caliber between and .*Length refers to the cartridge case length.*OAL refers to the overall length of the cartridge.All measurements are in mm .-Pistol cartridges:-.24in :...
diameter bullet, and is a high velocity round based on ballistics
Ballistics
Ballistics is the science of mechanics that deals with the flight, behavior, and effects of projectiles, especially bullets, gravity bombs, rockets, or the like; the science or art of designing and accelerating projectiles so as to achieve a desired performance.A ballistic body is a body which is...
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.
Design
The 243 WSSM is an addition to the Winchester Super Short MagnumWinchester 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...
(WSSM) family of cartridges, which also include the .223 WSSM
.223 WSSM
The .223 WSSM is a .224 caliber rifle cartridge created by Winchester and Browning based on a shortened version of the Winchester Short Magnum case.- History :...
and the .25 WSSM
.25 WSSM
The .25 Winchester Super Short Magnum is a third member of the Winchester Super Short Magnum cartridge family created by Winchester and Browning. It is the largest caliber of the WSSM's and is the most capable of handling large game such as deer and wild boar.It is a necked-up version of the .243...
, and the idea behind the 243 WSSM was to develop a compact, higher velocity version of the well-established and internationally popular .243 Winchester
.243 Winchester
The .243 Winchester is a popular sporting rifle cartridge. Initially designed as a varmint round, it is now more frequently used on medium to large game such as whitetail deer, mule deer, pronghorn, wild hogs, and even black bear and caribou...
unveiled by Winchester in 1955.
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
Deflagration
Deflagration is a term describing subsonic combustion that usually propagates through thermal conductivity; hot burning material heats the next layer of cold material and ignites it. Most "fire" found in daily life, from flames to explosions, is deflagration...
of propellant powder when it is held in a short, fat stack by the cartridge case.
Problems
Short fat cases with an abruptly angled shoulder have a history of being difficult to feed properly from the magazines of some rifles. In addition, during its short life the WSSM family of cartridges has already gained a reputation for being hard on gun barrels because of the high velocities involved when using lighter weight 'varminting' style projectiles, although this is a point of some dispute among various knowledgeable gun owners and expert writers.Some rifle manufacturers such as Browning
Browning Arms Company
Browning Arms Company is a maker of firearms, bows and fishing gear. Founded in Utah in 1927, it offers a wide variety of firearms, including shotguns, rifles, pistols, and rimfire firearms and sport bows, as well as fishing rods and reels....
have also taken to chrome-lining their barrels' bores to make them less susceptible to the wear caused by the high levels of bullet friction and very high propellant gas temperatures that occur with WSSM cartridges.
Performance
In their ballistics tables, WinchesterWinchester Repeating Arms Company
The Winchester Repeating Arms Company was a prominent American maker of repeating firearms, located in New Haven, Connecticut. The Winchester brand is today used under license by two subsidiaries of the Herstal Group, Fabrique Nationale of Belgium and the Browning Arms Company of Morgan, Utah.-...
list a very high muzzle velocity of 4060 ft/s (1,237.5 m/s) with a 55 gr projectile for this cartridge. Based on Hodgdon reloading data typical velocities should range from approximately 4000 ft/s (1,219.2 m/s) with a 58 gr bullet to approximately 3000 ft/s (914.4 m/s) with a 100 gr bullet. The percentage gain in performance over the older .243 Winchester is around 10% or less, and it remains to be seen if the market will offer a commercially viable place to two 6 mm sporting cartridges that have such similar performance.
This cartridge is usually used for small game such as varminting, and used for animals as large as deer
Deer
Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...
.
Advantages
Compared to other factory 6mm sporting cartridges the 243 WSSM is capable of functioning in the AR-15 platform. Other factory produced 6mm cartridges like the 243 Win. and 6mm Rem. are both too long for the AR-15 and require the much heavier and more expensive AR-10 platform.The 243 WSSM is 3/8 inch shorter than the 243 Win. giving the 243 WSSM the ability to fit an 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.
External links
- 243 WSSM – The Long-Awaited 6 mm "Answer"? By Bill Prudden
- The 243 WSSM 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