Whats the deal with 9mm

I've been struggling with reloading 9mm JHP. I realized tonight that I'm probably overcrimping. I'm working with Zero 115gr JHP. Do I understand correctly that minimal crimp is ideal? My .45 loads seem pretty good but 9 mm has proven challenging. I guess I'm looking for good fundamental techniques with 9mm and how they differ from .45. KKM 1-18 barrel. Thanks

1: 18 you have to run them hot. I use 6.4 gr Power Pistol on my 115gr bullets. With a light taper crimp.

Len

9mm overcrimping usually results in bullet setback in the magazine due to case mouth deformity.  Better to just crimp enough to remove the flare.  In the case of a revolver it will result in crimp jump.   I'd recommend the Lee Factory Crimp die.

Probably like rifles jacketed bullets rely on neck tension. Just get rid of the slight belling

Loading JHP as others have said, just remove the flare/bell of the case, can't get away with a tight crimp like with lead bullets.

Your crimp should measure .378 - .379 depending on the diameter of your bullet. Most 9mm cases have a wall thickness of .011.  Zero 9mm JHPs are about .3555 in diameter.

                  .356 (bullet) + .022 (both case wall thickness) = .378 crimp

Any less you will not have removed all the bell and any more and you are swagging the bullet.

Hope that helps.

Same bullet moving at 1,050 f/s out of my 9mm 1911 (16 inch twist) gave one inch rested groups at 25 yds.  Literally the first load I picked out of a book (Power Pistol).  Not picky at all.  Very slight crimp. Little kick and super accurate.