Description PRODUCT DETAIL:Caliber: 5.56 NATO Bullet Type: GMX Bullet Weight: 55Gr Muzzle Energy: 1196 ft/lbs Muzzle Velocity: 3130 fps Rounds Per Box: 20 Application: Performance/Protection Casing Material: Brass Firearms, trailers, and some accessories are only available for purchase in stores. Each location follows all BATF and individual state/county/city laws to insure the desired product is legal for sale. Any info provided online is subject to change, please go to your local store for more accurate information.