I am getting mixed messages from the local community on the need to taper crimp 9mm Luger with jacketed, copper plated or hard cast bullets. Any sage advice from the experienced elders

I would. You've got to turn the belled case mouth back in a bit anyway.

Definitely taper crimp Mac...the 9mm, like the .45...headspaces on the case mouth mate, so you can't have a roll crimp, but you do need to hold those boolits snug because of the sharp recoil pulse.

Cheers, Vince

Yes Mac, you need to taper crimp and NOT roll crimp because these cartridges seat at the head of the mouth and a roll crimp will bulge out the case a little to upset headspace.

I also tapercrimp my 9 mm's.
On the 45 ACP I even run an extra (4-th) die. Because on the 45 ACP the case is so thin you can see how far the bullet is seated, I put a bullet-seating-die of the 7x64 as last die, just to remove these bullet dent from the case. I haven't tried this on the 9 mm. Also I haven't tried other seating dies, but looking at the shape the 280 Rem or the 270 Win might also work.
Attention: this extra die is NOT to seat the bullet, it's only the straighten the case-walls (and improve feeding? Or just the looks?)

The only reason to taper crimp the mouth of a 9mm X 19, .45 ACP, .40 or any other auto round that headspaces on the case mouth is to insure that the bell has been removed. To crimp to increase bullet tention is a waste of time and can be detrimental to the bullet and headspacing and is unnecessary.

At this point I will leave my two pennys.

Great info and pretty well echoes my research I added a Lee Taper crimp die to my order.

You got it Mac

Bushmaster wrote:

To crimp to increase bullet tention is a waste of time and can be detrimental to the bullet and headspacing and is unnecessary.

Dead on advice. Excessive crimping (even taper crimping) can let the case mouth slip too far into the chamber and, if it is fired in this position, the additional constriction can cause pressures to rise to astronomical levels.

In reloading straight/taper wall cases that headspace on the case mouth we use a “taper crimp” die. However this die doesn't really “crimp” anything. It’s sole purpose in life is to remove the flair on the mouth of the casing so the round feeds and headspaces correctly.

A properly adjusted taper crimp die may or may not increase bullet tension by as much as 10%. Screw that die down further and the casing starts to buckle releasing it’s grip of the bullet.

Bullet tension is determined by:
1. The resizing die.
2. The expander plug. (Bell mouth die)
3. Case wall thickness.
4. Bullet diameter.

The best way I know to properly set up your taper crimp die is first resize a casing and measure the mouth diameter with a set of calipers. Now take that empty casing and run it through the taper crimp die and measure again. The two measurements should be the same, or no more than .002" smaller.

Bullet type will also plays a part as to th amount of taper crimp applied. The expander ball and bullets dia. provide the tension to hold the bullet in the case. To much taper crimp deforms the bullet reduces it size especially with plated/cast bullets.

Proper taper crimp applied to 9mm plated/cast bullet.


Excessive taper crimp applied to plated/cast bullet.

Yup...Excellent [example] photos, res45.

Agree wholeheartedly with Bushy...excellent examples RES45.

I think some might have misinterpreted my initial statement regarding taper crimping. What RES45 has said above explains it perfectly.

Cheers, Vince

Good job res45!

Good post Res45 I have ordered the LEE die and am only planning on pushing in leftover flare edge.

MacD, there is an article in the December 2010 issue of "Handloader" magazine about the 9mm cartridge and loading for it. I stumbled across it today. You might be able to find it online (I can't check from work). If not I'll try to scan it into a PDF file for you.