Two things to watch out for. One is OAL. Seating a bullet too deeply can get you into hot water very fast, by raising pressures through the roof, especially in small cases like the 9mm. Use the length recommended by the bullet maker if at all possible. The second is to taper crimp your auto-pistol loads so the measurement at the mouth is the same as factory to be sure the bullet doesn't get pushed deeper into the case and boosting pressures like #1 above. You can check if it’s tight enough by pressing a loaded round into a hard surface to see if it moves.
Also, check and double check the powder level in your cases before you start seating bullets. Stuff happens!
Go slow and be careful. Good luck with the search for “pieces” for your loads.
