The M14 sound comes from Call of Duty Black Ops, the 2010 Treyarch shooter where the rifle appears early in campaign and multiplayer as a high damage semi automatic option. Players ripped the firing audio for soundboards and editing packs alongside other FPS staples like the enemy spotted callout. It stayed popular because the Black Ops version sounds cleaner and punchier than many modern recordings, so creators keep reusing it for retro gameplay tributes, fake shooter scenes and nostalgic edits of early 2010s gaming.