Winchester NATO-Spec Navy Primers forty one are exactly the same primers Employed in the Lake Town 5.56mm ammunition. These primers are constructed to exacting technical specs for shot to shot consistency. All primers are continuously and rigorously analyzed for consistency and sensitivity at temperatures and situations significantly further than the variety of typical winchester 41 primers use. Winchester assures thoroughly-managed weights of primer mixtures, regularity in size and high quality, precise measurements and tolerances for anvil heights and stability in extremes of temperatures and humidity.