Just a few supporting statements of "Myth surrounding sound of shotgun racking"...
Firearms, ammo, weapons, gear reviews, 2nd Amendment issues, etc...: Mythbusting: The Racking of a Shotgun
Shotgun Myths | Rem870.com
Shotgun Myths
American Rifleman - 10 Movie Myths Dispelled
Fighting on Empty
With his pump-action shotgun leveled at his former accomplice, the hardened criminal growls, "Where's the gold, Luke?" Holding his hands up shaking his head side to side, the ex-bank robber cries, "I don't know what you're talking about Hank!" With hatred shining in his steely eyes, Hank briskly racks the slide on his shotgun and asks again, "Where's the gold, Luke?!"
That’s right folks, Hank was handling a functionally unloaded gun for the first few minutes of the conversation. Hollywood directors love the psychological effects produced by firearm actions being cycled. Thus shotguns are pumped, hammers are cocked and slides are racked frequently on screen for the audience to see. In fact, this racking action can be so important to the scene that the director will gladly shove characters into potentially dangerous situations with non-functional guns. Who would willingly walk into a gun fight with an empty chamber? According to film logic, having a gun that's ready to fire in the middle of a firefight is highly overrated.