.25 Winchester Super Short Magnum

The .25 Winchester Super Short Magnum is a third member of the Winchester Super Short Magnum (WSSM) cartridge family created by Winchester and Browning. It is the largest caliber of the WSSM line (excluding wildcats) and is the most capable of handling large game such as deer and wild boar.

Description
It is a necked-up version of the .243 WSSM, which is in turn a shortened .300 WSM (Winchester Short Magnum). The WSSM cartridges are based on ballistics design philosophies that are intended to produce a high level of efficiency.

Like the other WSSM rounds, the .25 is effectively a magnum in name, and energy-per-COAL, only. Performance wise it is nearly identical to the long action .25-06 Remington, making it well suited for medium to large game with the advantage of being usable by lighter short action rifles. Having the short fat design, the cartridge loads potentially burn at a more consistent rate, in theory providing a lower muzzle velocity standard deviation (SD) for increased accuracy. Performance is far less than true .25 caliber magnum rounds such as the .257 Weatherby Magnum. In fact, ballistically it's almost identical to the improved version of the .257 Roberts, which P.O. Ackley said was his favorite choice for an all-around cartridge.