I shot some of my Grampa's reloaded ammo a while back. From the note on the slip of paper in the box they were loaded in the late 1960's. They shot just fine, all went bang, all hit the target.
I also have some .45 ACP ball ammo that is head stamped of 58 none have failed to fire when I shot them.
No matter how many times you do it and nothing happens it only takes something going wrong one time to kill you.