Winchester NATO-Spec Military Primers 41 are the identical primers Employed in the Lake City five.56mm ammunition. These primers are created to exacting specifications for shot to shot regularity. All primers are consistently and rigorously examined for consistency and sensitivity at temperatures and problems considerably beyond the array of usual use. Winchester ensures diligently-managed weights of primer mixtures, winchester 41 primers consistency in dimension and good quality, precise measurements and tolerances for anvil heights and stability in extremes of temperatures and humidity.