Winchester NATO-Spec Navy Primers 41 are the same primers used in the Lake City five.56mm ammunition. These primers are constructed to exacting specs for shot to shot regularity. All primers are constantly and rigorously examined for regularity and sensitivity at temperatures and winchester 41 primers disorders considerably further than the range of normal utilization. Winchester ensures meticulously-managed weights of primer mixtures, regularity in dimension and quality, precise measurements and tolerances for anvil heights and security in extremes of temperatures and humidity.