What the folks who told you Carcanos are unsafe forgot to tell you is that they don't know what they were talking about. In general, no government wants their soldiers firing anything unsafe, no matter how lowly the soldier is. Bad for morale, you know. And the Carcano was one of the few actions PO Ackley could not blow up when he was testing actions to failure. Is it pretty? No. Marvel of engineering? No. Strong? Yes, at least as strong as it needed to be.
Never try to educate someone who resists knowledge at all costs.
But what do I know?