Winchester NATO-Spec Military Primers forty one are precisely the same primers Employed in the Lake City 5.56mm ammunition. These primers are created to exacting technical specs for shot to shot regularity. All primers are continuously and rigorously tested for consistency and sensitivity at temperatures and problems considerably further than the selection of typical utilization. winchester 41 primers Winchester ensures thoroughly-managed weights of primer mixtures, regularity in dimensions and excellent, specific measurements and tolerances for anvil heights and security in extremes of temperatures and humidity.