Winchester NATO-Spec Navy Primers forty one are the exact same primers used in the Lake Metropolis 5.56mm ammunition. These primers are crafted to exacting specs for shot to shot consistency. All primers are regularly and rigorously analyzed for regularity and sensitivity at temperatures and situations significantly outside of the selection of standard utilization. Winchester ensures thoroughly-managed weights of primer mixtures, regularity in dimensions and high-quality, winchester 41 primers specific measurements and tolerances for anvil heights and steadiness in extremes of temperatures and humidity.