Starline Unprimed 308 Win Brass (Large Rifle primer) – 100 The venerable .308 Winchester has made quite a name for itself since it was first introduced in 1952. The .308 and its military equivalent, the 7.62x51mm Nato, is a very efficient cartridge that has excellent ballistics, while still being fairly easy on the shoulder. That, and its inherent accuracy have kept it thriving as both a competition and hunting caliber.