Check your gun. My PA-63 chamber is cut long. It will barely catch the rim on a chambered round. The slide has to be dropped hard, or it'll just hang on the side of the rim. This doesn't matter, so long as the round fires. But in case of a malfunction, I wouldn't want to have any short cases.
I use a Lee, so I can't go back and make the pilot longer, unfortunately. Well, I guess I could if I broke out the lock-tite. My cases come out right at 18mm. If your cases chamber (and extract, unfired) out of your gun, then there's no problem.