Virginia Gun Owners Forum - VGOF

I am just starting out and want to know how much crimp for 9mm, what to look for and how to tell if it is enough? What happens if you have too much or not enough?

9mm Luger headspaces on the case mouth. Too much crimp (or a roll crimp) will allow the cartridge to seat too deeply, leading to light primer strikes by the firing pin/striker and other problems if the cartridge does fire. To light a crimp can allow the bullet to shift. Bullet shifts foward - chambering problems, stuck bullets, powder everwhere. Bullet shifts back - dangerous pressures in this small capacity case.

Are you belling the case mouth any prior to seating the bullet? What manuals are you using?
Temper this advice with the fact that I only have experience with .45 ACP. But caution is prudent with fast burning pistol powders...
Glen

If you are new to reloading 9mm you'll find that the cases have a very small tolerance for being "worked." Too much bell and crimp will severely shorten the case life since they are so thin. Watch for splits and cracks when reloading them. You'll see many...

Ditto above. Just started first of this year, loading 9mm, 45 and 380. What dies are you using? I use the Lee Factory Crimp Die in my classic turret press, and with it adjusted for a "light crimp" per the instructions, it seems to be just about right. If you havent already, get a couple of different manuals. My go-to manual lately seems to be my Sierra manual, but I also reference Hornady, Lyman, and Speers.

Another recommendation is to avoid the lighter bullets until you get a little experience loading 9mm. Reason is they are so short leaving very little bullet to seat in the case. It takes a bit practice to get something like the 90gr to sit right...you'll get the hang quickly and find they are pleasant to load and rewarding to shoot your own creations.