Winchester NATO-Spec Military Primers 41 are the same primers Utilized in the Lake Metropolis five.56mm ammunition. These primers are built to exacting specs for shot to shot regularity. All primers are frequently and rigorously tested for consistency and sensitivity winchester 41 primers 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 temperatures and humidity.