Winchester NATO-Spec Army Primers 41 are the identical primers Employed in the Lake Town five.56mm ammunition. These primers are developed to exacting technical specs for shot to shot regularity. All primers are continuously and rigorously tested for consistency and sensitivity at temperatures winchester 41 primers and problems considerably beyond the array of usual use. Winchester assures diligently-managed weights of primer mixtures, regularity in dimension and good quality, exact measurements and tolerances for anvil heights and balance in extremes of temperatures and humidity.