Way late on the reply, but the answer is sometimes. Usually you can't or it's at least very obvious.



I do a little reloading myself and whether or not you can double charge a cartage depends mostly on what kind of powder and what load you're using. Many powders have different volume to weight ratios.



Personally, I try to use powders that will overflow if i were to accidentally charge them twice. It's not a common mistake, but it's an extremely dangerous one.