Too Short of Cases?


September 23, 2011, 07:47 PM
I'm new to reloading and working on 40 SW. I was measure some of my cases and they were showing up between .830 and .834. So I was wondering how short under the trim to length of .840 can a case be, before it is too short to be safe. I've read that the trim to length is the minimum, but that was only in one place, and also read the straight wall cases tend to shorten over time so if they short over time, and they started out at .840 then one firing would make it unusable. Any help would be appreciated.

Thank You,

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September 23, 2011, 08:02 PM
Can't quote an exact number, but it seems to be pretty forgiving. The "trim to" number for 9x19 is .751" but I regularly reload cases that are .745" without difficulty or firing issues. A lot of it is going to depend on your gun since autos head space directly on the case mouth.

September 23, 2011, 08:03 PM
Measure them after you size them, not before.

They grow when you size them.

As for length being too short to headspace correctly?
Must have been long enough, or they wouldn't be empty cases now, would they?

My suggestion is to size them, measure them, then Fuggedaboutit!
If they worked the first time, they will work the second time.

I have never trimmed a straight wall pistol case that was too long, or thrown away one that was too short, in the 49 years I have been reloading them.


September 23, 2011, 08:24 PM
I have already resized them, and I think when I belled the cases they lost a lot bit of length.
Thank You,

September 23, 2011, 08:30 PM
Well O.K. then.

You most certainly can't measure them after you expand & bell them.

Measure them straight out of the sizer die.


September 23, 2011, 11:39 PM
So you've measured them after belling the mouths? If thats the circumstance, your still not getting an accurate measurement. Measure after resizing, like RCmodel said, and before belling. That number will be an accurate measurement. That belled mouth is deffinitely longer than what it's measuring at.

September 25, 2011, 10:15 AM
The only "measuring" I do with pistol brass is to stand all my 9MM brass up in batches when I get it back from a range where others will be shooting. If I see a short one it will be 380 or 9X18 not 9X19/9MM. Easy to spot that way and way faster than sorting by head stamps.:cool: That's the easy way to separate 38 SPL and 357MAG if they are mixed also.

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