Crimping for 9mm

[JLaw]

Mornin' all, got another question on loading the 9mm. Roll crimping my .38 Spl's, no problem, got that down. But how much taper crimp do I need to put on the bullet for a semi-auto? It's a little harder to see the amount of taper crimp you have vs. roll crimp. I adjusted my RCBS crimping die to just touch the case mouth at the top of the stroke, then ran it in another 1/2 turn.

Thanks to all,

JLaw

[KaiserB]

I try to taper crimp just enough to hold the bullet so it will not be pushed back into the case when fed. I think lymans manuals and others have a diameter (OD) for the outside of the brass.

This example appears to be 0.380 OD at the crimp:

[Houston1944]

Unlike the roll crimp which helps hold the bullet in place, the only purpose of the taper crimp is to just remove the "bell" from the case so the round will feed into the chamber of semi-autos. You do not want the taper crimp to cut into the bullet. A little trial and error will be needed to get the die set up correctly. Just keep adjusting the die slightly until the bell is gone and you have a smooth angle for the brass to slide on when it feeds from the mag into the chamber.

[MoJo]

Unlike the roll crimp which helps hold the bullet in place, the only purpose of the taper crimp is to just remove the "bell" from the case so the round will feed into the chamber of semi-autos. You do not want the taper crimp to cut into the bullet. A little trial and error will be needed to get the die set up correctly. Just keep adjusting the die slightly until the bell is gone and you have a smooth angle for the brass to slide on when it feeds from the mag into the chamber.

I don't taper crimp in my seating die I use the Lee factory crimp die. It is a Carbide post size and crimp die that assures your ammo is sized to specs after loading. It will remove all those little bulges you sometime get.

[Mike1951]

I use a case gage for semi auto cartridges that simulates your chamber.

Adjust in small increments until the loaded round drops freely all the way into the gage and will drop out easily.

Of course, some just take their barrel out and use this.

[ske1eter]

I don't taper crimp in my seating die I use the Lee factory crimp die. It is a Carbide post size and crimp die that assures your ammo is sized to specs after loading. It will remove all those little bulges you sometime get.

I've had good luck with the Lee crimp die as well.

[phddan]

Lee factory crimp die for the win.

Dan

[Houston1944]

I also use the Lee Factory Crimp Die for several of my handgun loads. Just to keep from confusing those that may not be famliar with this die let me clarify a couple of things. The LFC die is a taper crimp die for semi-auto calibers and a roll crimp die for revolver calibers. What sets it apart from other crimping dies is the secondary re-sizing that it performs while crimping.

Years ago I would have 5% or more (really cannot remember but it was a significant number) of my 38 Super loads that would fail to gauge. Once I changed to using the LFC die the failure to gauge rate dropped to zero. The secondary re-sizing made the problem go away.