Saying goodbye to 9MM .743" length cases

[sbwaters]

Hi, all ... In the last batch of 200 9MM Starline cases I resized and measured, about 15 measured .743 inches. SAAMI seems to say pitch them into the recycle bin.

I hate to do it, but feel obliged. Help me feel good about following the guidelines.

Thnx.

 

[kcofohio]

I don't have the drawing on my phone. But IIRC, .760" -.020 +0 is the tolerance for 9mm Luger for case length.

Edit: okay I found .754" -.010" +0 is the tolerance. My bad.

 

[mcb]

Can't help. I have never measured or trimmed a pistol case in my life. I just run them through the press and if they pass the case gauge they are good to go. If they fail the case gauge but pass the barrel plunk test they go in the practice box.

SAAMI spec for case length of 9mm Luger/9mm Luger +P is .754 -.010 inch. I personally would not sweat .001 under spec. Shoot them a few times they will grow.

 

[Walkalong]

Keep using them.

 

[Texas10mm]

Can't help. I have never measured or trimmed a pistol case in my life. I just run them through the press and if they pass the case gauge they are good to go. If they fail the case gauge but pass the barrel plunk test they go in the practice box.

SAAMI spec for case length of 9mm Luger/9mm Luger +P is .754 -.010 inch. I personally would not sweat .001 under spec. Shoot them a few times they will grow.

Actually they will shrink.

 

[WestKentucky]

Load to the same specs as other cases, crimp will be ever so slightly less. If you really worry about it then separate them out and turn your crimp die in another 1/16 turn. For .001 you could probably just put a feeler gage in the shell holder and run it like normal. That would hold it higher in the shell holder and therefore it goes higher into the crimp die.

 

[kcofohio]

The main thing is when the case mouth bottoms out in the chamber, that the firing pin can still detonate the primer.

 

[mcb]

Actually they will shrink.

You're probably right. Probably not enough pressure to stretch the body (or neck as in the case of a rifle cartridge) but enough to cause the case head to grow in diameter shorting the case.

 

[mdi]

Another school of thought is that the extractor will hold a cartridge in place strong enough to fire it. I wouldn't know because I haven't measured nor trimmed a semi-auto case in many years, if ever (older brains ferget unimportant things easily)...

 

[kcofohio]

Another school of thought is that the extractor will hold a cartridge in place strong enough to fire it. I wouldn't know because I haven't measured nor trimmed a semi-auto case in many years, if ever (older brains ferget unimportant things easily)...

Good point.

 

[Rule3]

People actually measure 9mm brass? I have 5 gal bucketfuls I need to check!
To .001"? How hard are you squeezing the calipers?
How much variance is there in different 9mm handgun cambers?

 

[Blue68f100]

Keep shooting them till you loose them. The extractor will hold the round well enough to fire. Now if your a High Master Marksman and have a gun setup for that, anything under 0.003" below the chamber will be tossed. Which cover 98% of my brass, as practice ammo. With only a few that are long.

 

[sbwaters]

Yeah, they shrink about .001 a reload.

People actually measure 9mm brass?

Hah! My OCD taking over [Actually, CDO, when spelled alphabetically].

After cleaning, I measure and throw them in different bins [.744, .745, ...], then package them into 50s in baggies. That way I’m confident similar batches will load with a consistent crimp in my LnL seat-and-crimp die on the progressive.

Thanks for the points of view and humor.

 

[IMtheNRA]

If someone really, really wanted longer cases, wouldn't using a small die, such as Lee's U die, squeeze the cases so much that they'll get longer?

 

[mcb]

If someone really, really wanted longer cases, wouldn't using a small die, such as Lee's U die, squeeze the cases so much that they'll get longer?

A roll sizer might get some of that back since it sizes the entire length of the case.

 

[Rule3]

Yeah, they shrink about .001 a reload.



Hah! My OCD taking over [Actually, CDO, when spelled alphabetically].

After cleaning, I measure and throw them in different bins [.744, .745, ...], then package them into 50s in baggies. That way I’m confident similar batches will load with a consistent crimp in my LnL seat-and-crimp die on the progressive.

Thanks for the points of view and humor.

Had you trimmed these cases ever??

Just for "fun" I went to my bench and randomly pulled 5 pieces of 9mm. This brass could have been loaded 5 to 20 times.
As random luck they are all different headstamps

Win .745
SB .749
RP .749
CBC .748
CCI .750
Never worried much about taper crimps, just load them and shoot them.

You probably clean primer pockets also?

What happens if you lose one of the fifty at the range?

 

[lightman]

Keep using them.

I agree!
I quit measuring auto pistol cases long ago. Most of them are short. I've never trimmed one. I have trimmed revolver cases when chasing the last .0001 in accuracy, just trying to get a uniform roll crimp. Even then I saw hardly any improvement. I sure wouldn't trash those cases.

 

[cougar1717]

I would keep loading them until you lose them.

If that is unacceptable, then please donate them to a poor 9x18 Mak user for a second life

 

[sbwaters]

What happens if you lose one of the fifty at the range?

You’re going to laugh ... Hell, you already are ... the bottom of the case is marked with an orange or green Sharpie so after an IDPA indoor match I can get ’em all.

... and outdoors I shoot mixed range brass that I don’t care if I lose.

... Wet tumble with pins. you got a problem with clean primer pockets? ... Heh! Bet you don’t clean under your fingernails either. ;-)

 

[rsrocket1]

If they fit in the case gauge or plunk in my barrels, they get loaded and shot.

 

[cfullgraf]

I cannot remember if I have ever measured the length of a 9x19 case. But, then, I've probably slept a bit since then.

For a .001" difference, I would not put it past the caliper being a bit off unless it had been calibrated recently.

Keep using them.

I agree as well.

 

[Dudedog]

This

If they fit in the case gauge or plunk in my barrels, they get loaded and shot

Maybe they might shoot more accurately if I trimmed them, but that would depend on me being able to shoot the difference if there is any.

Don't throw them out or recycle them

If that is unacceptable, then please donate them to a poor 9x18 Mak user for a second life

They deserve a second chance as MAK brass if you don't want them.

 

[joneb]

Sounds like good brass to make cases for a 9x18 Makarov.

 

[Rule3]

You’re going to laugh ... Hell, you already are ... the bottom of the case is marked with an orange or green Sharpie so after an IDPA indoor match I can get ’em all.

... and outdoors I shoot mixed range brass that I don’t care if I lose.

... Wet tumble with pins. you got a problem with clean primer pockets? ... Heh! Bet you don’t clean under your fingernails either. ;-)

Did you ever trim the offending brass??

I mark my brass with a Sharpie but still lose some.
Yes, I trim and clean my fingernails once a year if they need them or not!

 

[jmorris]

I agree with both “keep using them” and “they will shrink”.