Winchester NATO-Spec Armed service Primers forty one are a similar primers Utilized in the Lake Metropolis five.56mm ammunition. These primers are constructed to exacting requirements for shot to shot regularity. All primers are constantly and rigorously tested for consistency and sensitivity at temperatures and ailments far past winchester 41 primers the choice of normal usage. Winchester ensures diligently-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.