thumb|300px|WSM and WSSM family of cartridges. From left to right: [[.223 WSSM, .243 WSSM, .25 WSSM, .270 WSM, 7 mm WSM, .300 WSM, .325 WSM.]]
Winchester Short Magnum, or WSM, refers to a family of rebated 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. All of the WSM cartridges are inspired on the .404 Jeffery non-belted magnum cartridge which is shortened to fit a short rifle action (such as a .308 Winchester).
It was developed by Rick Jamison in 1997-1998 as shown in the 2003 lawsuit Jamison vs. Olin Corporation-Winchester division. Jamison was given 7 patents on the cartridge design. U.S. Repeating Arms Company used the same concept and the same base case in creating its even shorter Winchester Super Short Magnum cartridges, three of which were introduced in 2003 and 2004.
Influences
thumb|100px|The .300 Winchester Short Magnum demonstrates the accuracy of its name when compared to the .300 Winchester Magnum.
7.82 Lazzeroni Patriot
The WSM family was inspired partially by a family of proprietary short magnum cartridges developed in late 1997, by John Lazzeroni, derived from a previous line of magnum cartridges he had created. The first Lazzeroni short magnum, the 7.82 Lazzeroni Patriot,