Winchester NATO-Spec Army Primers 41 are exactly the same primers Utilized in the Lake City 5.56mm ammunition. These primers are created to exacting technical specs for shot to shot consistency. All primers are continually and rigorously examined for consistency and sensitivity at temperatures and ailments considerably beyond the array of usual use. Winchester assures diligently-managed weights of primer mixtures, regularity in sizing and quality, specific measurements and tolerances for anvil heights winchester 41 primers and steadiness in extremes of temperatures and humidity.