Winchester NATO-Spec Military services Primers 41 are exactly the same primers Utilized in the Lake Metropolis five.56mm ammunition. These primers are built to exacting requirements for shot to shot regularity. All primers are continuously and rigorously examined for consistency and sensitivity at temperatures and disorders far past the array of standard utilization. Winchester ensures thoroughly-managed weights of primer mixtures, regularity in dimensions and excellent, specific measurements and tolerances for anvil heights and security in extremes of temperatures winchester 41 primers and humidity.