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Alec Baldwin claimed he did not pull the trigger on the set of "Rust," but gun experts say that a revolver firing without the trigger being pulled is unlikely.

In a preview for an upcoming televised tell-all, Baldwin addresses the fact that he was holding a gun that was somehow loaded with a live bullet that should not have been on the set at all, let alone in an actor’s hand. The Oct. 21 incident left cinematographer Halyna Hutchins dead and director Joel Souza injured.

During the preview, which is heavily edited for the purpose of teasing the larger interview that’s set to air Thursday evening, an emotional Baldwin states unequivocally that he did not pull the trigger.

"The trigger wasn’t pulled. I didn’t pull the trigger," Baldwin told George Stephanopoulos.

Alec Baldwin claimed he did not pull the trigger during a preview for an upcoming tell-all interview regarding the fatal shooting on the set of ‘Rust.’

Alec Baldwin claimed he did not pull the trigger during a preview for an upcoming tell-all interview regarding the fatal shooting on the set of ‘Rust.’ (Photo by Sonia Moskowitz/Getty Images)

ALEC BALDWIN SAYS HE DID NOT PULL THE TRIGGER IN FATAL ‘RUST’ SHOOTING INCIDENT: ‘I WOULD NEVER’

He adds: "No, no, no, no, I would never point a gun at anyone and pull the trigger. Never."

The Santa Fe Sheriff's Department said it is awaiting results from the FBI which would shed light on how the gun could have been fired, whether that was just pulling back the hammer – which hits the firing pin – just pulling the trigger or both.

"Guns don't just go off," Sheriff Adan Mendoza told Fox News Digital. "So whatever needs to happen to manipulate the firearm, he did that and it was in his hands."

The fourth search warrant released by the Santa Fe Sheriff's Department shows armorer Hannah Gutierrez Reed suggested someone on the set had potentially pulled the hammer back on the .45 Colt revolver during her interviews with police.

(Photo by OGUT/Star Max/GC Images)

Despite Baldwin's assertion, gun experts say firing a revolver without pulling the trigger is unlikely unless there was some sort of 'mechanical failure.' (Photo by OGUT/Star Max/GC Images)

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"We had the gun the whole time before that and nothing happened, and I wasn't in there, and they weren't even supposed to be pulling the hammer back," Gutierrez Reed was quoted saying in the search warrant.

In October, a weapons expert told Fox News Digital that since "Rust" is set in the 1880s, production could be using a single-action revolver appropriate for the time period. It’s been reported that the gun Baldwin was holding is an F.LLI Pietta Long Colt 45 Revolver. 

Weapons armorer Bryan W. Carpenter told Fox News Digital on Wednesday firing a revolver like the one Baldwin was reported to be holding without pulling the trigger would be "rare."

"In order to make it fire, you have to put your thumb up onto the hammer, cock the hammer all the way back, and then as the hammer is completely cocked back, then you pull the trigger and then the gun fires," Carpenter explained. "So that's very important because that gun had to have two step process to fire. It had to be cocked and the trigger pulled to fire."

The Santa Fe Sheriff's Department said it is awaiting results from the FBI which would shed light on how the gun could have been fired, whether that was just pulling back the hammer – which hits the firing pin – just pulling the trigger or both.

The Santa Fe Sheriff's Department said it is awaiting results from the FBI which would shed light on how the gun could have been fired, whether that was just pulling back the hammer – which hits the firing pin – just pulling the trigger or both. (Fox News Digital)

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Once you have the gun cocked, Carpenter explained it doesn't take much to pull the trigger.

"Once you cock the hammer back on one of those old west guns, it doesn't take a lot to set that trigger off," he told Fox News Digital. "You know, they're very light triggers."

The modern-day Glock handgun has around a five-pound trigger pull, according to Carpenter, "whereas one of those old westerns could have a two pound trigger on it, which is half or less than half of what a modern gun has," he said.

Film and prop historian Michael Corrie explained to Fox News that firing a revolver without pulling the trigger would require a "mechanical failure."

"The hammer needs to be fully locked to the rear for the weapon to function," Corrie explained. "Which necessitates manual operation of the weapon."

"Barring an as yet unknown mechanical failure, this weapon did not fire itself," he stated, adding that: "For the hammer to travel forward at all, the trigger has to be depressed... unless some major mechanical failure takes place." 

Fox News Digital has reached out to Baldwin and Gutierrez Reed for comment.

Fox News' Tyler McCarthy contributed to this report.