Winchester NATO-Spec Military Primers 41 are a similar primers used in the Lake City 5.56mm ammunition. These primers are designed to exacting technical specs for shot to shot consistency. All primers winchester 41 primers are continually and rigorously examined for consistency and sensitivity at temperatures and ailments considerably beyond the array of standard utilization. Winchester ensures thoroughly-managed weights of primer mixtures, regularity in measurement and excellent, specific measurements and tolerances for anvil heights and security in extremes of temperatures and humidity.