.223 Winchester Super Short Magnum
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.223 WSSM with 75 gr (4.9 g) Hornady AMax bullet
|Place of origin||USA|
|Parent case||.300 WSM|
|Bullet diameter||.224 in (5.7 mm)|
|Neck diameter||.272 in (6.9 mm)|
|Shoulder diameter||.544 in (13.8 mm)|
|Base diameter||.555 in (14.1 mm)|
|Rim diameter||.535 in (13.6 mm)|
|Rim thickness||.054 in (1.4 mm)|
|Case length||1.670 in (42.4 mm)|
|Overall length||2.36 in (60 mm)|
|Rifling twist||1-7" to 1-9"|
|Primer type||Large rifle|
|40 gr (3 g) BT (boat-tailed)||4,352 ft/s (1,326 m/s)||1,683 ft·lbf (2,282 J)|
|60 gr (4 g) JSP||3,733 ft/s (1,138 m/s)||1,857 ft·lbf (2,518 J)|
|75 gr (5 g) BT(boat-tailed)||3,378 ft/s (1,030 m/s)||1,901 ft·lbf (2,577 J)|
|Test barrel length: 24"
Source(s): Hodgdon 
The .223 WSSM was introduced in 2003 by the Browning Arms Company, Winchester Ammunition, and Winchester Repeating Arms Company. It is a shortened .300 WSM (Winchester Short Magnum) case necked down to accept a .224 caliber bullet. The .223 designation is a reference to the popular .223 Remington. It is currently the fastest production .22 caliber round in the world with muzzle velocities as high as 4,600 feet per second (1,402 meters per second).
Even before the cartridge was commercially introduced, many were claiming that it would be extremely hard on barrels (a "barrel burner" in gun parlance), and some still argue that it is a good varmint round for long distances but is very hard on barrels and is not good for medium game any farther than 200 yards.
The Winchester made Model 70 in .223 WSSM has not been revived in the new Browning-made Winchester Model 70s, but Browning has chosen to use chrome-lined barrels on all of its guns chambered for .223 WSSM and has introduced the .223 WSSM cartridge as a chambering in its A-bolt rifles. Browning rejects the charge that the .223 WSSM round is especially hard on barrels: "The 223 and 243 WSSM cartridges are said to 'burn up' barrels in as little as 300 rounds. Nothing could be further from the truth."
According to Browning, the .223 WSSM offers a 600 ft/s (180 m/s) gain, with a 55 gr (3.6 g) bullet, over the standard .223 Rem. It also offers a 440 ft/s (130 m/s) gain over the 22-250, a popular varmint round. This comes out to a 600 ft·lbf (810 J) gain over a standard .223 Rem, and a 350 ft·lbf (470 J) gain over the 22-250.