Would it be possible to change the firing mechanism in prop guns so that they can't fire live ammunition?

Aidan,
Most prop guns cannot fire at all and ones used for blank firing can be so constructed that live ammunition cannot be fired.
That said many thousands of blank rounds are fired every year in simulated fire fights by military personnel with no injuries.
It’s all down to training and common sense.
Baldwin called the US NRA a terrorist organisation, had he taken their shortest safety course he would probably not have taken a loaded gun and fired it without checking its status.

Foxy,
It’s not quite true that no one knew that one of the guns had live ammunition in it; that someone is the person that loaded it.
Which brings up a whole new scenario.j

Issy, Alex Baldwin didn't shoot anyone. It was his mate Alec Baldwin. The irony of this high profile shooting is it took place on a film set that looked like Dodge City in 1880. Some members of the Shooters and Hooters Party and their coalition partners in One Nation would like to see Australia with the same lax gun laws that applied in Dodge City in 1880.

Issy, you know that SSAA members were complicit in the murders of Jack and Jennifer Edwards, they trained their father John Edwards in the deadly use of hand guns. They also sold him guns.

ttbn, please show some respect for Is Mise, he is now an honorary member of the GREENS

Personally I think charges should be laid against Baldwin, the armorer and the person who handed him the gun.
Charge them all, and see where the chips fall.
I don't care if its a movie set, it you point a gun at someone and pull the trigger, then it's your job to check its not loaded first.

Teach actors who use guns on set responsible gun safety, even if only blanks.
Teach them the difference between blanks and real bullets, and make it their responsibility to check before use.

Is there a genuine need for real bullets on set?
Maybe they need bullet holes in things for a true effect.

I bet the people who left the set in protest hours earlier were glad they did.
- It seems there were quite poor systems of management in place.

Paul,
As usual your sense of reality and history are deficient, no Australian gun owner wants to see Dodge City 1880s gun laws in this country; heaven forbid.
Suggest you do a bit of Googling on the subject of Dodge City and it’s laws.

Regarding Edwards he was considered a fit and proper person to have pistols by the NSW Commissioner of Police and that’s where the buck stops.
Twist things how you like you can’t escape that irritating fact.