Winchester NATO-Spec Armed service Primers forty one are the exact same primers used in the Lake City 5.56mm ammunition. These primers are designed to exacting specifications for shot to shot consistency. All primers are consistently and rigorously examined for regularity and sensitivity at temperatures and circumstances 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 winchester 41 primers of temperatures and humidity.