I suspect this case is nothing more than deflection, as imagine the armourer is likely the person who will get the harshest punishment out of the three of them.
It definitely seems an odd case to try and prosecute, going by the above picture it wouldn't take a professional to recognise there is a difference between live ammunition and blank rounds. So for someone who is supposed to be a professional in firearms, would be able to spot the difference from a mile away.
Something really stinks.
There were no blank rounds involved. The case against the ammunition supplier says nothing about blank rounds. The death was not caused by a blank round. Any mention of blank rounds is a red herring.
Surely, the person who loaded the gun would have noticed the live rounds?
That
should happen. It is easy to mistake a real round (live) and a dummy (not live). Blank rounds are also live rounds, but they weren't involved so the distinction is between real rounds and dummies. Dummies look the same as real rounds - that's the whole point of them. What should happen is that a suitably experienced person, someone who can detect the difference between a real round and a dummy, should check each round
individually when loading the gun and keep the loaded gun in their possession until they hand it to the actor for a scene and then take it back afterwards. In this case someone (who knows who?) loaded the gun from an unsecured store of ammunition and left it on an open table for who knows how long then someone else handed it to the actor. And maybe someone else loaded the gun with other ammunition too - it's been claimed that the prop guns were not secured and were sometimes loaded with real rounds and used for target shooting for sport outside of filming. It's not yet known (and might never be known) exactly what happened.
The only scenario in which the ammunition supplier is responsible is if they made dummies that were wholly indistinguishable from real rounds (which shouldn't happen) and supplied the set with a mixture of real rounds and those incorrectly made dummy rounds. Maybe that's what happened, but my money's on multiple firearm safety protocol violations on the set.