Primers Small Rifle AR Match No. 205M Size: 0.210-inch Primer Style: Small rifle bench rest Cups are thin for a heated charge and cup is sealed to prevent flash leakage. Flash hole uniformity enhances the ability of flame to reach all powder granulations at the same time and create efficient combustion. Performance is maximized by matching Federal primers with Federal ball powders, which were designed by engineers who understand how the ignition characteristics of primers must work with the burn rate of powder. This insures consistency and reliability round after round. Package of 1,000