reloading 9mm,40SW and 45ACP

[gutterman]

I have been reloading off and on for about 20 yrs, but never have concentrated on the "auto" cals. Most of my reloads have been 38/357,45LC,44mag. What I would like to know is, how much crimp is really necessary, or is the "standard" crimp provided by the bullet seating die sufficient for the 9mm, 40SW and the 45ACP?

 

[Walkalong]

All those calibers need is a very light taper crimp. Just enough to remove the bell, or a hair more. (.001 to .002) No more is needed. Neck tension does all the work.

http://www.thehighroad.org/showpost.php?p=6284211&postcount=63

 

[243winxb]

"standard" is a taper crimp, this can be applied by your seating die or with a separate taper crimp die. Remove the bell from the case mouth. Measure the body right behind the case mouth. The taper area should be .002" smaller than the body. Walkalong beat me by 1 min.

 

[gutterman]

thanks guys for the input-I'll check the measurements.

 

[rfwobbly]

Mr Gutter -
Allow me to restate what the other guys have already told you. With revolver rounds you typically roll the end of the case into a groove on the bullet. This is a true "crimp" called a "roll crimp".

On auto cartridges you need a sharp edge to stop the forward movement of the cartridge as it goes into the chamber. Auto cartridges use the "taper crimp" to remove the case mouth belling so that the cartridge case can fit all the way into the chamber. So a "taper crimp" is not really a crimp at all; it's more of a clean up process.

Here's a rudimentary graphic...


Just as with revolver dies, the seating die (3rd position) can also apply the taper crimp. If you have a multi-station progressive press, some people apply the taper crimp in the 4th position as a matter of convenience.

Hope this helps!