338 Edge (.338/300 Ultra Mag, .338 Ultra Cat) is a Wildcat rifle cartridge based on the .300 Remington Ultra Magnum round necked up to accept 0.338" diameter bullets. It is gaining popularity as a long-range cartridge due to the wide availability of 0.338" projectiles with favorable ballistics. For instance, the -grain ( g) Sierra Match King has a ballistic coefficient of 0.765 and is a popular choice for 338 Edge shooters.[citation needed]