extractor mark
Technical term in firearms examination: the mark left on a cartridge case by the extractor mechanism. Compare 蹴子痕 (kicker mark).
See also: 蹴子痕
The forensic investigator compared the extractor marks on the cartridge cases.
蹴子痕 refers to the mark left by the ejector (kicker), while 抽筒子痕 is specifically the mark from the extractor.
Compound of 抽筒子 (extractor) + 痕 (mark, trace). The exact historical derivation is uncertain; the term is used in modern forensic firearms examination.