Crimping 9mm

[Vloc1987]

So as far as 9mm, Is it okay for a light crimp or heavy? I’m using the lee factory crimp die for them and just curious how much of crimp I need.

 

[drband]

Enough to remove the flare. That’s enough.

 

[JimKirk]

Taper crimp .... but only enough to bring the "belling" back straight ...

 

[Ironicaintit]

What drband said...

just remove the bell

 

[chamokaneman]

I'm still learning with my 9mm loading. I've measured before and after with my calipers and decided a thousandth or so is enough. I've also plunked into my case gauge and barrel and stopped when it plunks. I think you'll hear universally that less is more.

 

[Walkalong]

As posted, just enough to remove any flare/belling when you expanded the case.

 

[rfwobbly]

I never did get the "light and heavy crimp" thing. There's a point where it's easy to buckle the case if you apply too much crimp to a 9mm round, so that too much crimp is just as bad as not enough crimp. Either way the round won't chamber... which is the whole point of the taper crimp in the first place !!

Here's a place any novice can start...

Think about this... Since taper crimp is solely to remove the belling, if you carefully seat a bullet into a sized but un-flaired case, then the finished diameter of that case mouth is (generally) the same diameter your crimp die should be taking your flaired/belled cases during production.



Typically on 9mm, this diameter ends up measuring between 0.377 and 0.379". And of course this is only measured at the case mouth. You've got to remember that the 9mm family of cartridges are all tapered. Measuring away from the mouth may give you false readings.



Hope this helps.

 

[film495]

in the press when I've done 9mm, you just need to be able to feel each round touch the crimp die, and it should not be very stiff or hard, just touching up into the crimp die removes the belling, if you can feel it touch they should all plunk.

 

[mdi]

I have been reloading semi-auto rounds for some time now, and I don't "crimp" any, I use a plain old taper crimp die to just deflare, never an FCD. 32 ACP, 380 ACP, 9mm, 45 ACP...