Winchester NATO-Spec Navy Primers forty one are precisely the same primers Employed in the Lake City 5.56mm ammunition. These primers are designed to exacting specifications for shot to shot consistency. All primers are continually and rigorously examined for regularity and sensitivity at temperatures and disorders far past the choice of normal usage. Winchester guarantees very carefully-controlled weights of primer mixtures, consistency in dimension and good quality, exact measurements and tolerances for anvil heights and security in extremes of temperatures and winchester 41 primers humidity.