Winchester NATO-Spec Armed forces Primers 41 are the exact same primers used in the Lake Town 5.56mm ammunition. These primers are designed to exacting requirements for shot to shot regularity. All primers winchester 41 primers are regularly and rigorously examined for regularity and sensitivity at temperatures and ailments considerably beyond the number of standard use. Winchester guarantees meticulously-managed weights of primer mixtures, regularity in size and high-quality, precise measurements and tolerances for anvil heights and stability in extremes of temperatures and humidity.