Winchester NATO-Spec Armed service Primers forty one are a similar primers used in the Lake City five.56mm ammunition. These primers are crafted to exacting technical specs for shot to shot consistency. All primers are continuously and rigorously analyzed for regularity winchester 41 primers and sensitivity at temperatures and disorders significantly over and above the range of ordinary utilization. Winchester assures very carefully-managed weights of primer mixtures, regularity in measurement and high-quality, exact measurements and tolerances for anvil heights and security in extremes of temperatures and humidity.