Short 9mm Case Length

[.223Savage]

I was sitting facing a pile of sized 9mm cases when in a moment of foolishness I decided to measure some of them. A quick look at a manual showed the dimensions should be .749-.754". The first few I measures tended to be .745", i.e. about .004" shorter than the minimum, it got worse as I measured more of them. After measuring about 60 of the sized cases close to a third were .004" or more below the minimum dimension. Only 2 were longer than the maximum .754".

I had stopped measuring my 9mm brass and just sized, primed and loaded them after a visual inspection. Virtually all of this brass is range pickup that I and/or others have shot. I don't know how many times it has been fired.

It is simple enough to trim any long ones but it is the large number of short cases that have me concerned. Given that 9mm headspaces on the case mouth, I am worried that I am asking for trouble if I use the cases that measure below the minimum length. It is not like I don't have lots of them, I probably have another 1000 or so that I have picked up over the years.

My question for the wise members here is should I simply scrap those cases that measure below the minimum dimension? I value my guns, hands and eyes more than trying to squeeze another firing out of these cases. Is this a typical phenomena, I thought cases usually grow in length?

Your thoughts and comments are appreciated.

 

[CeeZer]

Just load and shoot. In practical terms those are just fine.

 

[superted]

Maybe sort by headstamp?

 

[UR2X3M4ME]

Pretty well anyone new a reloading pistol calibers ask this one. I did.

You did read your reloading manuals so thumbs up to you. Not poking at you: just a few days ago, one fellow reloading pistol loads was considering getting a scale 'cause he thought his loads were hot...

Straight walled pistol cases headspace on case mouth. No need to measure them, nobody does. Just a) Inspect for cracks/split cases; b) and reload; and c) have fun shooting them.

 

[Ganderite]

Load and shoot. I have loaded several hundred thousand 9mm, and have yet to measure an empty case. I do pay attention to OAL because my CZ has a short throat.

 

[OldDude]

I wouldn't worry about 0.004". 0.040", definitely....

 

[Becks357]

Load and shoot. I have loaded several hundred thousand 9mm, and have yet to measure an empty case. I do pay attention to OAL because my CZ has a short throat.

That

 

[Cerdan]

Is this a typical phenomena, I thought cases usually grow in length?

Bottleneck cases grow after repeated firings, which is why they need to be trimmed and why, eventually, they become prone to head separation if the reloader isn't careful.

Straight-walled cases, however, tend to shrink; the resizing die pushes material towards the head, sometimes causing a visible "bulge" at the base of the case after multiple reloads.

Other than that, what everyone else said: Just load'em and shoot!

 

[CeeZer]

It happens if you get a .380 case mixed in such case shouldn't activate powder drop either.