I have been reloading for 25 or more years and have rarely had a problem. When I did have one it was generally attributed to inattention. The failures I have had were due to no powder, or low powder in the case. No damage to anything other than my ego, but things can go south real quick it you don't pay attention. My latest example of this was with a .38 Special wadcutter in a S&W 52-2. The primer detonated and pushed the 148 gr wadcutter about halfway out of the case and locked the pistol up. I don't know exactly how that happened because I use an RCBS lock-out die on my progressive reloader, but it did happen. In reality the saving grace was the pistol locking up with the slide slightly held open so no chance of firing another round. The RCBS lock-out die has saved me a few times in the past from "no powder" loads, but this time it didn't. Perhaps it was a low powder load instead of a "no powder" load. Anyway, the point is you can never fall asleep at the switch when reloading, nor be too careful.
Rick H.