Persistence of Subclass Carryover in Smith & Wesson M&P15-22 Rifle Firing Pins

In 2016, firing pin impressions observed in test shots obtained from nineteen Smith & Wesson M&P 15-22 rifles displayed subclass carryover. This follow-up research was conducted to determine if the subclass characteristics observed in firing pin impressions would change during the firing of 3,500 cartridges from each of two .22 Long Rifle caliber Smith & Wesson M&P 15-22 rifles.