Winchester NATO-Spec Army Primers 41 are the same primers Utilized in the Lake Metropolis five.56mm ammunition. These primers are constructed to exacting requirements for shot to shot regularity. All primers are continuously and rigorously examined for consistency and sensitivity at temperatures and ailments far past the choice of ordinary usage. Winchester guarantees very carefully-controlled weights of primer mixtures, consistency in winchester 41 primers measurement and excellent, specific measurements and tolerances for anvil heights and steadiness in extremes of temperatures and humidity.