Winchester NATO-Spec Military services Primers 41 are the identical primers Employed in the Lake City 5.56mm ammunition. These primers are designed to exacting specifications for shot to shot consistency. All primers are consistently and rigorously analyzed for regularity and sensitivity at temperatures and circumstances significantly further than the selection of standard utilization. Winchester guarantees very carefully-controlled weights of primer mixtures, consistency in dimension and good quality, exact measurements and tolerances for anvil heights and security winchester 41 primers in extremes of temperatures and humidity.