When I first began loading for pistols, I had the same thing happen without the gun attempting to go into battery. I knew exactly what happened. I changed the steps of reloading on my single stage, to include changing the attitude of the brass in the block after each step. Head up prior to charging, neck up prior to bullet seating. Although there is no 'need' to visually check that all the cases are charged doing it this way, I still look down into the block to verify.