Winchester NATO-Spec Armed service Primers forty one are the same primers Utilized in the Lake City five.56mm ammunition. These primers are designed to exacting requirements for shot to shot consistency. All primers are continuously and rigorously examined for regularity and sensitivity at temperatures and problems much past the variety of ordinary usage. Winchester ensures diligently-controlled weights of primer mixtures, consistency winchester 41 primers in sizing and excellent, specific measurements and tolerances for anvil heights and stability in extremes of temperatures and humidity.