Starline Unprimed Brass Cases 358 Win (50pk) - RNA. K. A 8. 8x51mm 2. 003 2. 008 O. A. L. Based on the . 308 Winchester, the . 358 Winchester was introduced by Winchester in 1955 for use in lever and bolt action rifles. While it had not seen the widespread popularity as the other . 308 based cartridges, its brush busting capability still makes it an excellent choice for hunting any of North America's big game. With the recent rise in popularity of AR 10 style rifles, the . 358 Winchester is starting