Winchester NATO-Spec Army Primers forty one are the exact same primers Employed in the Lake City five.56mm ammunition. These primers are developed to exacting requirements for shot to shot regularity. All primers are frequently and rigorously analyzed for regularity and sensitivity at temperatures and winchester 41 primers ailments significantly further than the range of normal use. Winchester ensures meticulously-controlled weights of primer mixtures, regularity in dimensions and excellent, precise measurements and tolerances for anvil heights and stability in extremes of temperatures and humidity.