Winchester NATO-Spec Armed service Primers 41 are a similar primers used in the Lake Metropolis five.56mm ammunition. These primers are crafted to exacting specs for shot to shot regularity. All primers are continually and rigorously analyzed for consistency and sensitivity at temperatures and conditions significantly beyond the variety of winchester 41 primers regular utilization. Winchester assures meticulously-managed weights of primer mixtures, regularity in dimension and high quality, exact measurements and tolerances for anvil heights and security in extremes of temperatures and humidity.