I was in the process of loading shells for my Uncle's 300WBY last summer, when he provided me with a box of shells that would not fire (which he had previously loaded a few years earlier). "Must be bad primers" he said. As soon as I picked the "bad" shells up, I could feel that they had no powder in them! I extracted the bullets to see that the primer fired, but did not have enough oomph to push the bullet out of the casing. He was lucky!