I quoted above the New Mexico statute on involuntary manslaughter which says in the relevant part: “the commission of a lawful act which might produce death in an unlawful manner or without due caution and circumspection.”
It seems that the statute provides ample scope for the prosecutor to obtain a conviction under the facts as we know them today. I note that the prosecutor need not even prove that the act committed “without due caution and circumspection” need not produce death but he must only prove that it “might” produce death.
In assessing whether there was a failure of due caution and circumspection it would seem that the well accepted rules for the handling of firearms, together with the specific rules and statutes regulating the use of firearms on movie sets would be entirely relevant for the jury to consider.
Baldwin has a tough case here so I expect him to try to lay the blame entirely on co-defendants.
If his action was "reckless" - i.e. so incredibly negligent (in the judgment of the jury) to constitute implied intent, then he is guilty of "reckless conduct", a misdemeanor - but that misdemeanor creates a felony *murder* charge. If he is not guilty of that level of negligence he may still be guilty of "unlawful manner manslaughter", another way of saying "without due caution and circumspection". That would be a misdemeanor and won't trigger a felony murder charge.
That's probably what's really going on here.