Winchester NATO-Spec Military Primers 41 are the exact same primers Utilized in the Lake City 5.56mm ammunition. These primers are crafted to exacting specifications for shot to shot consistency. All primers are constantly and rigorously tested for consistency and sensitivity at temperatures and circumstances significantly beyond the variety of typical utilization. Winchester ensures thoroughly-managed winchester 41 primers weights of primer mixtures, regularity in dimension and high quality, precise measurements and tolerances for anvil heights and stability in extremes of temperatures and humidity.