.300 Remington SA Ultra Mag

.300 Remington Short Action Ultra Magnum (also known as 300 RSAUM, 300 RSUM or 300 Rem SAUM) is a .30 caliber short magnum cartridge that was put on the market shortly after Winchester released its 300 WSM round in 2001.

Performance
The 300 RSAUM's ballistics are similar to 300 Win Mag and 300 WSM. The difference in ballistics between the WSM and RSAUM are fairly minuscule.

Muzzle velocity

 * 10.69 g (165 gr) Full Metal Jacket(FMJ): 3,075 ft/s
 * 11.66 g (180 gr) Full Metal Jacket(FMJ): 2,960 ft/s

Comparisons

 * The WSM has slightly more case capacity and thus, slightly more velocity
 * The WSM is more popular and more ammo and handloading data are available