Winchester NATO-Spec Military Primers 41 are a similar primers Employed in the Lake Town five.56mm ammunition. These primers are crafted to exacting technical specs for shot to shot regularity. All primers are constantly and rigorously analyzed for consistency and sensitivity at temperatures and problems significantly over and above the range winchester 41 primers of normal use. Winchester ensures meticulously-controlled weights of primer mixtures, regularity in dimensions and good quality, precise measurements and tolerances for anvil heights and steadiness in extremes of temperatures and humidity.