New unprimed NAS3 .300 BLK (7.62x35mm) cartridge cases. Shell Shock's NAS3 cases: Up to 50% lighter than brass cases Offer greater lubricity and will not abrade, clog, foul, wear-out or damage breach and ejector mechanisms. Offer greater corrosion resistance, tensile strength, and elasticity than brass. More consistent round-to-round performance Will not split, chip, crack or grow (stretch) Eject cool to-the-touch and can be picked up with a magnet Suitable for small rifle primers The bullet will only require a light crimp (we'd recommend a slight crimp using a Lee Collet Factory Crimp Die) - the nickel alloy used in our case cylinder has a much higher tensile strength than brass and does not require the bullet be seated as deeply or crimped as hard as brass. If you find the bullet spins or appears lose after crimping it is a strong indication that the bullet is seated too deep in the case.