Winchester NATO-Spec Armed forces Primers 41 are the identical primers Employed in the Lake Town five.56mm ammunition. These primers are developed to exacting requirements for shot to shot regularity. All primers are constantly and rigorously tested for consistency and sensitivity at temperatures and problems considerably beyond the variety of usual use. Winchester assures carefully-controlled weights of primer mixtures, regularity in size winchester 41 primers and high quality, precise measurements and tolerances for anvil heights and stability in extremes of temperatures and humidity.