.243 WSSM Load Data

Introduced in 2003, the .243 Winchester Super Short Magnum (WSSM) is a modern rifle cartridge developed jointly by Winchester and Browning. Its design was part of the WSSM series, created to provide short, fat cartridge cases capable of high velocity and improved efficiency over older designs. The .243 WSSM is essentially a shortened and necked-down version of the .300 WSM case, tailored to accept .243-inch bullets. Its case length of 1.670 inches results in a notably stubby profile compared to the iconic .243 Winchester, allowing the .243 WSSM to be chambered in very short-action rifles and benefit from reduced action weight and overall length. This innovation catered to hunters and shooters looking for a compact, high-performance round, especially popular among enthusiasts interested in the latest cartridge technology.

In practical terms, the .243 WSSM quickly developed a reputation for delivering high velocity and flat trajectory, making it exceptionally capable in the hunting and varmint shooting arenas. Its speed and energy deliver excellent performance on small to medium-sized game, rivaling or surpassing the traditional .243 Winchester in terms of raw ballistics. This has captured the interest of reloaders seeking to maximize velocity and downrange energy from a compact cartridge. The .243 WSSM also stands out due to its efficient powder burn, giving reloaders the ability to experiment with a range of modern powders while maintaining consistent velocities and pressures. However, due to its relatively short case neck, handloaders should pay close attention to bullet seating and neck tension for optimal performance and accuracy.

The primary applications for the .243 WSSM are varmint hunting, predator control, and light big game hunting. Its flat-shooting nature and high velocity are ideal for long-range shots on coyotes, foxes, prairie dogs, and groundhogs, as well as for deer-sized game in regions that allow centerfire rifles. The cartridge provides sufficient energy and minimal recoil, a combination that appeals to both novice and experienced shooters. The .243 WSSM is sometimes chosen as a competition round for certain long-range or precision disciplines, although more traditional cartridges tend to dominate those fields. Its strong points remain in field applications where quick handling, light recoil, and high-speed projectiles are advantageous.

In terms of target species, the .243 WSSM excels with small varmints and is equally effective for deer and antelope at reasonable distances. Its high speed ensures reliable expansion when using lighter bullets on varmints, while heavier bullet constructions work well on the vitals of medium game. Ethical hunters appreciate its ability to deliver flat trajectories that minimize guesswork over typical engagement distances. For reloaders, this means the caliber is both versatile and able to accommodate a range of bullet designs and weights that cover most hunting needs below elk size.

Typical bullet weights for the .243 WSSM range from 55 to 100 grains, with varmint loads favoring lighter 55–70 grain projectiles, and big game hunters opting for 85–100 grain bullets for deeper penetration and controlled expansion. The cartridge is capable of pushing 55-grain bullets at velocities approaching 4,000 fps, and 100-grain hunting bullets at over 3,100 fps, depending on powder choice and barrel length. Its short, wide case contributes to efficient powder burning and excellent feeding in short-action rifles, though some handloaders note that careful attention to case neck thickness and bullet concentricity is important for best accuracy. The .243 WSSM remains a unique choice in the modern reloader’s repertoire, blending advanced cartridge design with proven field performance for those seeking a balance of high velocity, efficiency, and versatility.