Winchester NATO-Spec Military services Primers forty one are the identical primers Employed in the Lake City 5.56mm ammunition. These primers are designed to exacting specifications for shot to shot consistency. All primers are regularly and rigorously analyzed for regularity winchester 41 primers and sensitivity at temperatures and circumstances much outside of the range of typical utilization. Winchester guarantees meticulously-controlled weights of primer mixtures, consistency in measurement and excellent, exact measurements and tolerances for anvil heights and security in extremes of temperatures and humidity.