Caliber: 243 Winchester - Weight: 80 Grains - Bullet Type: Gilding Metal Expanding - Muzzle Energy: 2083 ft lbs - Muzzle Velocity: 3425 fps - Casing Material: Brass - Rounds Per Box: 20 - Superformance ammunition is 100 to 200 fps FASTER than any conventional ammunition on the market today and achieves this performance in EVERY gun WITHOUT increases in felt recoil muzzle blast temperature sensitivity fouling or loss of accuracy. Superformance is a cutting edge technological advancement in ammunition design that transcends convention and achieves the highest performance of any ammunition on the market today.