Winchester NATO-Spec Military services Primers forty one are precisely the same primers Utilized in the Lake Town 5.56mm ammunition. These primers are built to exacting requirements for shot to shot regularity. All primers are regularly and rigorously tested for consistency and sensitivity at temperatures and disorders much further than the choice of typical utilization. winchester 41 primers Winchester ensures cautiously-controlled weights of primer mixtures, consistency in dimension and high-quality, specific measurements and tolerances for anvil heights and stability in extremes of temperatures and humidity.