In today's America, the tool of choice is the AR-15. Magtech offers 5.56 and 300 Blackout ammunition in several different loads to match what your rifle shoots best. If a battle rifle is more your speed, our 7.62 will reliably feed your big gun and make the hits downrange. First Defense Tactical Rounds Specifications Brand Magtech Category Centerfire Rifle Rounds Caliber 5.56x45mm Model First Defense Series Tactical Bullet Weight 55 gr Rounds Per Box 50 Casing Material Brass Application Tactical, Training Boxes Per Case 20 Bullet Type Full Metal Jacket (FMJ) Muzzle Energy 1302 ft-lbs Muzzle Velocity 3265 fps