Winchester NATO-Spec Navy Primers 41 are the identical primers Employed in the Lake Metropolis five.56mm ammunition. These primers are developed to exacting specifications for shot to shot consistency. All primers are frequently and rigorously examined for regularity and sensitivity at temperatures and circumstances significantly beyond the array of ordinary usage. Winchester ensures diligently-controlled weights of primer mixtures, consistency in measurement winchester 41 primers and quality, precise measurements and tolerances for anvil heights and balance in extremes of temperatures and humidity.