SANTA FE, N.M.—The account of the fatal shooting on the movie set of “Rust” in affidavits prepared by the Santa Fe County Sheriff’s Office suggests that some industry-standard safety precautions weren’t followed, say film-weapons experts and industry veterans.

Hannah Gutierrez Reed, the movie’s 24-year-old firearms expert, who had recently completed her first film as head armorer, wasn’t the person who handed the gun that was fired to actor Alec Baldwin, according to the affidavits. That deviates from standard practice, say...

SANTA FE, N.M.—The account of the fatal shooting on the movie set of “Rust” in affidavits prepared by the Santa Fe County Sheriff’s Office suggests that some industry-standard safety precautions weren’t followed, say film-weapons experts and industry veterans.

Hannah Gutierrez Reed, the movie’s 24-year-old firearms expert, who had recently completed her first film as head armorer, wasn’t the person who handed the gun that was fired to actor Alec Baldwin, according to the affidavits. That deviates from standard practice, say other armorers and film-industry veterans.

Dave Halls, the assistant director who handed Mr. Baldwin the gun, according to the affidavits, shouldn’t have been the one to do so, the experts say. Mr. Halls, Ms. Gutierrez Reed and Mr. Baldwin didn’t follow the typical standard protocols to ensure a gun’s safety on set, according to film-weapons experts and people with industry experience who reviewed the public details.

“Every time we hand off a gun on set to talent, we show the chamber, bore and magazine,” said Chandler Cornblum, vice president of Movie Armaments Group, a Toronto-based weapons supplier. “The actor has to signal they accept the gun is empty. Only then do I hand the gun off.”

A call sheet viewed by The Wall Street Journal for the set of “Rust” on Oct. 21, the day the shooting occurred, provides details of the guns on set assigned to different characters: a Colt that Mr. Baldwin’s character uses, a Remington and two other guns whose makes and models aren’t specified. The call sheet also lists a “Sharp rifle,” which likely refers to a Sharps rifle, according to an industry veteran.

A person familiar with the set confirmed Mr. Baldwin was using a Colt revolver when the incident occurred.

The shooting killed cinematographer Halyna Hutchins, 42 years old, and wounded director Joel Souza, 48. Moments before the shooting, Mr. Baldwin was sitting inside the church on the Old West movie set outside Santa Fe, rehearsing a scene, according to one of the affidavits. He reached across his body to pull the revolver from a holster, then pointed the gun at the camera lens, according to the documents released by the sheriff’s office.

Mr. Souza and another crew member said they weren’t certain the gun was checked for safety after a lunch break, according to the affidavits. Mr. Halls grabbed one of three prop guns laid out on a rolling cart and handed it to Mr. Baldwin to film a scene. He yelled “Cold Gun,” indicating the firearm didn’t have live rounds, according to the affidavits. Mr. Baldwin took the gun and fired it, an affidavit said.

The authorities are still investigating the shooting, including what kind of projectile was fired. Santa Fe area District Attorney Mary Carmack-Altwies

said Tuesday that her office hasn’t yet determined whether any charges are warranted. According to a list of inventory collected by the Santa Fe County Sheriff’s Office and filed in Santa Fe Magistrate Court on Monday, a detective obtained boxes of ammunition, nine spent casings and three black revolvers.

According to one the affidavits, Mr. Souza “stated there should never be live rounds whatsoever near or around the scene.”

The company created to produce the film, Rust Movie Productions LLC, has said that the safety of its cast and crew is its priority and that it was “not made aware of any official complaints concerning weapon or prop safety on set.” Film production has been halted, and the company has said it that would conduct an internal review of its procedures while production is paused and that it would continue to cooperate with authorities.

Mr. Baldwin has said he is cooperating with the Santa Fe County Sheriff’s Office investigation. “There are no words to convey my shock and sadness regarding the tragic accident that took the life of Halyna Hutchins, a wife, mother and deeply admired colleague of ours,” he said.

Ms. Gutierrez Reed, Mr. Halls and Mr. Souza didn’t respond to requests for comment.

Under industry protocols, any gun used for a film is supposed to be transferred by the armorer rather than passed among other people, according to armorers and film-crew veterans. An armorer should be in charge of the weapon at all times and should give it directly to an actor, according to the people who have worked on sets.

A safety meeting involving the armorer and assistant director, who functions as the film’s top safety officer, is typically held when a gun is about to be used, said Mr. Cornblum. Once it is time to film, depending on the scene, the armorer is supposed to shine a flashlight into the gun barrel to show the actor that it is safe and what it is loaded with—namely whether it is empty or has blanks or dummy rounds—according to Mr. Cornblum.

Larry Zanoff, a firearms expert and Hollywood veteran, said, “There shouldn’t be a situation where I walk up and blindly hand you a gun.”

The scene of “Rust” being rehearsed at the time involved a close-up of the gun, according to people familiar with the filming. Dummy rounds, as opposed to blanks, are typically used in such scenes to give a more realistic appearance of real bullets in the gun, according to Bruce Bisenz, a veteran live-action sound mixer. The dummy rounds are often used in revolvers—such as the Colt Mr. Baldwin used—where the cylinder shows the bullet tips when viewed from the front, he said.

Dummy rounds are cartridges that look real and have what appear to be a bullet in them, but no gunpowder, said N.R. Jenzen-Jones, director of Armament Research Services, a weapons and munitions analysis group. Blank rounds are cartridges that have been loaded with gunpowder but don’t have a projectile, or bullet, at the end. They make noise and cause a flash at the end of the barrel but are designed not to fire a projectile, he said.

“Right now, the way this is being painted is that guns are unsafe on a film set,” said Mr. Cornblum. “Certain procedures are industry norms, and they’re safe.”

—Joe Flint contributed to this article.

Write to Ben Kesling at benjamin.kesling@wsj.com, Katherine Sayre at katherine.sayre@wsj.com and Dan Frosch at dan.frosch@wsj.com