AFTE Store - Examination of Consecutively Manufactured Metal Injection Molded Breech Face Inserts from the Smith & Wesson M&P Shield EZ M2.0 Pistol

Smith & Wesson (S&W) has produced a new line of pistols called the M&P Shield EZ M2.0 that utilizes a removable metal injection molded (MIM) breech face insert. These inserts are produced exclusively through the MIM process, which is known to have the potential for subclass characteristics. To evaluate for potential subclass carry over, ten consecutively manufactured breech face inserts were obtained from Smith & Wesson, and it was found that each breech face surface displayed random and unique granular marks that can be used to distinguish inserts from one another. Although the granular marks were random, each breech face shared gross mold marks that were present in most inserts but varied in their position and size. Partially open test sets were created with 15 unknown test fires which included test fires produced using an 11th breech face insert that was not a part of the consecutively manufactured set, and 10 known test fires that originated from each of the 10 consecutively manufactured breech face inserts. Three examiners completed an examination of these test sets and it was found that all examiners correctly reported the origin of each cartridge case, with no misidentifications. This lack of identification errors suggests that the breech face inserts have individual markings that can be used for identification and to distinguish them from one another.