Winchester NATO-Spec Armed service Primers 41 are a similar primers used in the Lake Metropolis 5.56mm ammunition. These primers are built to exacting specs for shot to shot consistency. All primers are frequently and rigorously analyzed for regularity and sensitivity at temperatures and situations significantly outside of the range of typical utilization. Winchester ensures thoroughly-managed weights of primer mixtures, regularity in dimensions and high-quality, specific measurements and tolerances for anvil heights and steadiness in extremes of winchester 41 primers temperatures and humidity.