I have the worst shame so far: I loaded a double charge of Blue Dot in my .257 Wby Mag. The result was catastrophic!
This was fully my fault. It could have been prevented. I know what led up to the event--I was distracted during my reloading session with a "honey do" project and when I returned I put another charge in an already charged case. I was also in a hurry and didn't look inside the cases with a flashlight, as I normally do--I would have caught it if I had done that. I also didn't weigh the finished products, which I usually do when there is a chance of a double charge. I WAS LUCKY for this could have been catastrophic for me as well, but I only suffered some minor cuts on my face.
I learned a lot of lessons the hard way that day! More than anything, reloading must be approached with full attention. Don't allow yourself to be distracted and don't get in a hurry. Establish a routine with checks and balances and stick to it.