Crimp...diddilyimp

[RPatton]

Consistent crimp is necessary for feeding, avoidance of setback, and not damaging the bullet. You should be measuring it when you fiddle with your dies just as you'd measure OAL. A couple of thousandths caused by the variation of case thickness isn't even A Thing for PPC shooters, but you should have some idea how much you're crimping in the first place. That said, since my crimp changes approximately never, I don't worry too much about it.

I rolled with the old fingertip micrometer for a while, but why in the world would you halfass it when measurement is so easy?

Just be aware that crimp or lack of it will not prevent bullet setback. Crimp can cause your gun to key hole.

And by the way, 9mm has a tapered case so you can't check that the sides are parallel.

[Sarge]

Consistent crimp is necessary for feeding, avoidance of setback, and not damaging the bullet. You should be measuring it when you fiddle with your dies just as you'd measure OAL. A couple of thousandths caused by the variation of case thickness isn't even A Thing for PPC shooters, but you should have some idea how much you're crimping in the first place. That said, since my crimp changes approximately never, I don't worry too much about it.

I rolled with the old fingertip micrometer for a while, but why in the world would you halfass it when measurement is so easy?

Just be aware that crimp or lack of it will not prevent bullet setback. Crimp can cause your gun to key hole.

And by the way, 9mm has a tapered case so you can't check that the sides are parallel.

Agree with your first statement, except to add that lack of crimp will also lock a gun up tighter than Dick's hat band

[thermobollocks]

Just be aware that crimp or lack of it will not prevent bullet setback. Crimp can cause your gun to key hole.

And by the way, 9mm has a tapered case so you can't check that the sides are parallel.

I've found the first point to be demonstrably false depending on the gun, and the third moot since I started measuring.

[RPatton]

Consistent crimp is necessary for feeding, avoidance of setback, and not damaging the bullet. You should be measuring it when you fiddle with your dies just as you'd measure OAL. A couple of thousandths caused by the variation of case thickness isn't even A Thing for PPC shooters, but you should have some idea how much you're crimping in the first place. That said, since my crimp changes approximately never, I don't worry too much about it.

I rolled with the old fingertip micrometer for a while, but why in the world would you halfass it when measurement is so easy?

Just be aware that crimp or lack of it will not prevent bullet setback. Crimp can cause your gun to key hole.

And by the way, 9mm has a tapered case so you can't check that the sides are parallel.

Agree with your first statement, except to add that lack of crimp will also lock a gun up tighter than Dick's hat band

Crimp is what goes in a cannelure, like that on some jacketed bullets.

[Bob DuBois]

First Stage sizing die holds the bullet. Crimp alows the round to chamber easily.. While I'm a huge fan of Lee's sizing dies and use a Lee seating die I'm not a fan of the FCD.

This die was used to crimp Lee's tumble Lube bullets not standard bullets. Too much crim and accuracy will suffer. Use a Dillon crimp die, measure the case with the bullet seated

subtract .002 that's where I set the crimp. 9mm usually measures .380 so set crimp at .378.

I spend time sorting 9mm brass as it can vary a lot. Trash military cases because of the swagged primer and case volume is less. Trash any cases that have splits, chigger bites

or any other issues. Easiest way using three plastic factory trays. Place two in a box open side up, pour brass into trays most will land base down. Lock in the cases for trash or

pooblems and remove, standard pencile eraser works fine. Place the third tray over the first them flip like a primer flip tray. Look at the bases for swagged primers odd case marks

or any other reason to trash. The factory cases with square pockets work best. While looking turn the tray sideways and you can easily spot .380's or supers that worked there way

in the tumbler.

Always lube cases makes the whole process easier on the brass, dies, press and the operator.