'Rust' Assistant Director Gives Emotional Testimony During Armorer Trial

The first assistant director on the set of "Rust" -- who handed Alec Baldwin the gun that was ultimately fired at Halyna Hutchins -- just took the stand in the armorer's trial, and he cried.

David Halls testified on behalf of the prosecution Thursday in New Mexico -- where they're going after Hannah Gutierrez-Reed on manslaughter charges ... and he gave a detailed description of his last interaction with Halyna before she died on set.

It's incredibly emotional ... he says Halyna told him she couldn't feel her legs before she passed -- and DH sheds some tears here.

The prosecution also had a producer on the film, Ryan Winterstern, testify Thursday. Prosecutors say Hannah previously claimed she spoke to 2 producers named Ryan and Nathan and told them she needed additional armorer time with Baldwin concerning his cross draw.

Remember ... Alec was working on his cross draw in the scene when his gun went off and shot a live round, hitting Halyna and ultimately taking her life. Prosecutors say Hannah shares at least some of the blame because she was responsible for the guns on set.

Anyway, Ryan was asked straight up if he remembers having that conversation with Hannah ... and he testified he didn't recall her ever bringing that to his attention, and said he probably would remember such a convo if it had occurred.

Meanwhile, in testimony from Wednesday, prosecutors asked line producer Gabrielle Pickle if she ever expressed concerns to Hannah about firearms being left unattended on set.

Gabrielle testified she twice raised the issue with Hannah ... in person and also via email.

Asked if she suggested a way of fixing the issue with unattended firearms on the "Rust" set, Gabrielle testified she proposed a logging system to Hannah, where the firearms would be checked in and checked out with each use.

Gabrielle testified Hannah shot down the suggestion ... allegedly telling Gabrielle it was "too complicated" and that Hannah was working with her own system for keeping track of the guns.

As we reported ... the prosecution's opening statement was all about Hannah being at fault for the live round that killed Halyna.

Prosecutors said Hannah did not follow proper gun safety protocols on set ... claiming she regularly left guns and ammo just lying around the set, and even allowed live ammo to infiltrate the production.

For her part, Hannah's lawyers have said she was tasked with multiple jobs on set -- armorer and prop assistant -- which was a lot to ask of her at just 24 years old.