Winchester NATO-Spec Military Primers 41 are the identical primers Employed in the Lake Town 5.56mm ammunition. These primers are created to exacting technical specs for shot to shot consistency. All primers are continually and rigorously examined for regularity and sensitivity at temperatures and disorders far over and above the number of normal usage. Winchester guarantees winchester 41 primers carefully-managed weights of primer mixtures, consistency in size and top quality, precise measurements and tolerances for anvil heights and balance in extremes of temperatures and humidity.