Ultimate Arms Gear ST Action Pro Pack of 10 Inert .223 REM Remington 5.56 NATO M16 AR-15 M4 Rifle Yellow Safety Trainer Cartridge Dummy Ammunition Ammo Shell Rounds with Brass Case Pack of 10 - These Trainer Cartridges are Inert Dummy Rounds Used for Training and Instructional Activities. Developed for Military and Law Enforcement Use - Brass case with ABS Plastic Insert Makes the Round Highly Visible. Popular with Many Departments and Agencies for Use In Immediate Action Training for Just That Reason. Completely Inert Dummy Training Round. Excellent for Classroom Training, Loading/Reloading Drills, Gun Handling Drills, Malfunction Drills and Diagnosing Shooting Problems. Each Round Uses A Solid Brass Case So There Is No Chance of Rim Breakage. Ultimate Arms Gear Designed by ST Action Pro.