Honestly, I see no reason why they need to use real guns as props. Given the budgets, making some very realistic dummy guns which give realistic muzzle flashes and kickbacks should be very doable. Those dummy guns would be designed NOT to accept common rounds/calibers.
My brother was an extra in a cowboy movie years ago. No firearm on the location could fire a real bullet.
There were inserts in the chambers of every one of them that could only accept the 3 in 1 universal movie blank, which the inserts were shaped to take. Regardless of the original caliber of the rifle or revolver, they could only be loaded with those special cartridges, and only that single blank cartridge was present.
That is one reason you will never see an empty cartridge on the ground at a shootout, nor a clear image of a man reloading. Those blanks are clearly different from any cartridge you have ever bought or seen away from Hollywood. Gunmen never reload from their belt, because those are all "Wooden bullets" a nickname for completely fake artifacts that look right, but are not even as heavy as normal ammunition.
Cartridges that do appear on screen are placed there by the prop guys, from their collection of the correct sizes for the guns being used. If you watch carefully, most of the time that a "Winchester" lever action is fired, and lever operated, no empty blank is ejected, better you see nothing, than you see something that is clearly not a large rifle round.
In a previous post, I described being at a simulated gunfight, and saw those blanks first hand, up close. There is no possibility of confusing them with any real cartridge with a projectile in it.
Holding a blank and a real cartridge in your two hands, the weight is radically different, the blank is less than half the weight of the lightest load for a .38 caliber cartridge, and one quarter of a .45. The podcast where the armorer reported having to call her dad to learn how to tell the difference is flat amazing.
From the target practice and fun shooting by cast and crew, the revolvers were not fitted with blank adapters, and safety blanks were not being used.