Winchester NATO-Spec Military services Primers forty one are precisely the same primers Utilized in the Lake Metropolis 5.56mm ammunition. These primers are constructed to exacting specifications for shot to shot regularity. All primers are frequently and rigorously analyzed for consistency and sensitivity at temperatures and situations far beyond the range of normal utilization. Winchester guarantees carefully-managed weights of primer mixtures, regularity in dimensions and top quality, specific measurements and tolerances for anvil heights winchester 41 primers and security in extremes of temperatures and humidity.