Question: Trim to length

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pcgunner

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Probably a dumb question, but it's been awhile and in need of a refresher...

I was inspecting and measuring some brass - 9mm, the trim to length in my book says .751 with the max at .754

The measurements I took on my brass were .748-.750 - am I missing something?

Can't trim to length if the measured length is less than the trim to length?

Thanks in advance
 
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From Nosler:
All cases (aka – brass) have a few different length specifications: SAAMI maximum, SAAMI minimum, a “trim to” length that is typically .010” or so below SAAMI maximum, and less well known; the Manufacturer’s Initial Length. Because new cases are often slightly smaller in diameter than a fired and resized case, some allowance needs to be given for the initial case stretch that can occur when fired in the chamber. Because of this allowance, the Manufacturer’s Initial Length will sometimes be slightly shorter than SAAMI minimum length. Rest assured, this is absolutely fine and the cases will “grow” into specification as they are fired and resized the first few times.
Usually as long as you load to the suggested OAL (especially in auto's) you should be fine.
 
There is no need to ever measure or trim 9mm or other straight wall auto brass. Never ever. An exception might be .357 Sig, bottleneck.

Even if there were a need, when the length after resizing is less than the "trim to" length, it's fine. This applies to revolver and rifle brass too.
 
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You are fine with your brass. I never measure or trim straight wall handgun brass. However, twice in the past year I loaded a 9mm case that did not pass the plunk test (I test all my loaded rounds in the tightest chambered barrel I own which is the M&P 9 FS barrel) and found that the brass was actually too long. I should have kept it for posterity, but instead simply disassembled the cartridge, stomped on the case to make sure I wouldn't use it and put it in my brass recycling jug.

If I run across one again, I'll note the headstamp and dimensions.
 
IMO, as long as the cases are less than max-you should be good to go. I used to trim my 38 Special PPC Match Brass years ago. I did a test, trimming 100 pieces of 45 acp brass back to .888" (.898" max). took a lot of time/effort for no visible difference in accuracy. So, unless my brass sticks out from my Lyman Case Length Gauge; it gets loaded as is. Far less chance auto brass will need trimmed, than revolver brass.
 
Excellent responses and greatly appreciated

It is also as I was expecting which is also good for me - tells me I haven't forgotten everything.

Wife and I reloaded for 10 years 20 years ago and been out of it for too long.
 
You don't "have to" trim pistol brass and most people don't. If your 9mm brass is too long the gun may not go into battery, if the brass is too short, you might get light firing pin strikes and failure of ignition.

I always trim my revolver brass, you only have to do it once, this allows me to seat and crimp in one step and I don't get any buckled cases. For auto loader brass, usually I just lock my calipers at the midway point between the maximum length and the trim to length then use them as a gauge, anything that is too long gets trimmed, anything that fits between the jaws doesn't.
 
Some many years ago a few of us at the gun club got into a discussion about case length. To prove a point I trimmed a lot of 38 Special brass to precisely the same length (all same head stamp brass), and loaded a target load of 158 SWC cast bullet. We shot it in a well tuned Mod 19, and shot it out of a Ransom Rest. I wish I still had the target. It was the most beautiful 10 shots inside the X ring you ever saw. Do I still trim my brass? Only revolver brass when I first load it.
 
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I have never trimmed a 9mm case, or a 45 ACP case. And I have loaded thousands of them now. They have all worked perfectly. I can see an argument with revolver cartridges, but in my experience, you can still get away with not trimming those.

Mike
 
Yes some trim revolver brass, It helps with perfect crimps, but as mentioned it is probably a one time deal.

I have trimmed 38 special brass and keep it separated for shooting the M 52 semi auto, wad cutter pistola.;)
 
If I 'scored....

If I scored myself and didn't like my performance I'd adjust my shooting the best I can and if that isn't enough I'll start with the details on the ammo, but I can't see me doing that. I just try to get a good group in the center of the target. Right now I just plain don't shoot well enough to get down to minutia. And only my 686 is inherently accurate enough to try to shoot bullseye with.
 
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Been reloading pistol brass since 1962; never trimmed a one. Don't plan to.

9mm being a little quirky, I do check each loaded round in a case gauge. I do not, however, use the "plunk" test. Mine go "plook".

Now rifle rounds, that's a whole 'nother thing.
 
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