I once loaded a 300WM with a partial load of H4350, about 12 grains by what was left in the measure, and didn't notice it… Following weekend I found that round when I pulled the trigger during a practice match, it went click, no bang, and when I turned the bolt the rifle hissed and the rim of the case was bent. The case mouth was all melted and burnt, the 190g CC bullet was wedged in the barrel about 4" in front of the chamber, no brass rod would budge it, had to ream it out of the barrel in the end. This is the only reloading mistake I didn't catch. Have had several mistakes since, but all were caught and rectified, I also stopped pouring powder and seating bullets straight after because of this incident. I do each stage as a set, pour powder in all cases, check powder heights, if ANY look suss, they get weighed again and adjusted if need be, then all get bullets seated. Have not had a missing or partially missing charge since doing this.
Have never had a misfire, hangfires when developing loads for wildcats, yes, but no scary incidents.
Cheers.