Winchester NATO-Spec Army Primers 41 are exactly the same 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 winchester 41 primers rigorously examined for consistency and sensitivity at temperatures and ailments considerably beyond the variety of ordinary use. Winchester assures carefully-controlled weights of primer mixtures, consistency in size and top quality, exact measurements and tolerances for anvil heights and balance in extremes of temperatures and humidity.