Statistically speaking
In either case, adult or child, a relative percentage of the outcomes will turn out tragically, no matter how carefully you monitor or regulate the process.
However, in absolute terms, the number of tragedies can be minimized, even if they can never be eliminated altogether.
Its a lot like surgery. Sometimes it is necessary, and often it is useful, but if you do it too often, or for no good reason, it will eventually lead to pointless heartbreak.
Limiting access to firearms will never eliminate crime or accident, but it will make them less likely. But the gun lobby has always had trouble with the distinction between "not possible" and "not probable". In fact, maintaining that myopia is their central strategy.