Winchester NATO-Spec Military Primers forty one are exactly the same primers Employed in the Lake Town five.56mm ammunition. These primers are developed to exacting specs for shot to shot regularity. All primers are constantly and rigorously analyzed for consistency and sensitivity winchester 41 primers at temperatures and circumstances significantly outside of the number of typical usage. Winchester ensures thoroughly-controlled weights of primer mixtures, regularity in size and high quality, exact measurements and tolerances for anvil heights and steadiness in extremes of temperatures and humidity.