First Defense Features 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 Specifications Caliber: 300 Blackout Model: First Defense Series: Tactical Bullet Weight: 200 gr Rounds Per Box: 50 Casing Material: Brass Application: Tactical Training Bullet Type: Full Metal Jacket Subsonic Muzzle Energy: 459 ft lbs Muzzle Velocity: 1017 fps