The 325 WSM or .325 Winchester Short Magnum, commonly known as the 325 WSM is an 8mm caliber rebated rim bottlenecked centerfire short magnum medium bore cartridge. The cartridge was introduced by Winchester Ammunition in 2005. This cartridge is simply the 300 WSM necked up to accept the .323″ bullets.
The .325 WSM is an efficient, flat shooting 8mm magnum rifle cartridge. Bullet weights range from 125 to 250 gr (8.1 to 16.2 g). Performance is on par with the two other magnum cartridges: 8mm Remington Magnum and the German 8×68mmS cartridge with lighter weight bullets. However, these later two cartridges have a distinct edge of being able to seat long heavy 220 gr (14 g) bullets without encroaching upon the powder space. Due to the necessity of seating heavier longer bullets more deeply into the powder column due to the short design and maximum overall length of the .325 WSM cartridge, velocity drops off as bullet weight increases. This is particularly evident with mono-metal bullets such as Nosler’s E-Tip bullets, and the Barnes X bullets. These bullets are constructed of copper, which is about 20% less density than that of a conventional lead bullet. The resulting mono-metal bullets are typically longer, which requires these bullets to be seated more deeply to meet standards set for the cartridge and allow reliable feeding and cycling of the cartridges in rifles.