Such stories always amaze me how folks can be so lax in their own safety and by lack of proper procedures for shooting. Nope it has never happened to me and I'd not expect it ever will. I NEVER EVER have to different calibers on the bench at the same time. NEVER. No exceptions. I keep each different round in its own box clearly marked as to what is in it. When I sit down to shoot I look at the caliber marking on the box and rounds and make sure they are same as rifle being fired. No exceptions ever.
It's just like the safety precautions one must take to safely reload ammo. Not everyone seems to realize that if you are in any way distracted by other events going on around you then you should NOT be reloading or shooting. Both tasks require 100% of your mental faculties at all times.
I agree. This is only common safety sense. But I've worked around the oil and gas industry for enough years to know that people get lax and that's when accidents occur. I certainly make sure I have the correct ammunition.
As far as guns marked wrong....Many years ago a friend and I were in a gun shop in Eastern OH. In the used rack was a really nice bolt action marked 30-06. I was shooting a Remington 760 at the time in 30-06 and he wanted a bolt in 30-06. We both looked the gun over, checked the bore, and everything looked great.
We took the gun back to his mother's farm where he had a bench and target range set up. He put a target at 25 yards and fired. No hit on the paper. He's telling me to watch again and he fires the 2nd shot. I don't see where it hit, but I commented that the gun sounded "funny." Well, we checked the fired case and it was blown out to 35 caliber. The gun had been rebarreled to 35 Whelen Improved and was still marked 30-06. Why we didn't notice the 35 caliber bore, I'll never know, but the gun shop sold it as a 30-06. After we went back and complained to the gun shop, he actually ended up keeping the gun and reloading for it.
Luckily in this case all we did was resize the brass, but it it had been rebarreled to a 270, it would have been big problems.