Winchester NATO-Spec Armed forces Primers forty one are precisely the same primers Employed in the Lake Town 5.56mm ammunition. These primers are created to exacting technical specs for shot to shot regularity. All primers are continuously and rigorously examined for consistency and sensitivity at temperatures and ailments considerably beyond the variety of usual use. Winchester winchester 41 primers assures very carefully-controlled weights of primer mixtures, consistency in dimension and good quality, exact measurements and tolerances for anvil heights and balance in extremes of temperatures and humidity.