Winchester NATO-Spec Army Primers forty one are the identical primers Employed in the Lake City 5.56mm ammunition. These primers are crafted to exacting specifications for shot to shot consistency. All primers are consistently and rigorously analyzed for regularity and sensitivity at temperatures and conditions much over and above the number of normal usage. Winchester guarantees very carefully-controlled weights of primer mixtures, consistency in measurement and good quality, exact measurements and tolerances for anvil heights and security winchester 41 primers in extremes of temperatures and humidity.