9mm brass length - how picky are you?

barnfrog

barnfrog

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I was going through some data to work up some 9mm Luger loads for the Berry's 124-grain HBFP plated bullets I picked up, and while I was at it decided to check the trim length so I could check all the processed range brass I have. I noticed the Lyman manual says trim-to length is .751", Western (Accurate) says .749", and Hornady and Speer say .744". My Lee trimmer takes cases down to 0.748". When I started measuring brass, I found 0% were as long as Lyman says the minimum length is. Every single one was under .750". About 60% were between .744" and .749", and around 40% were less than .744". There were even some that were under .740". I tossed everything .733" and shorter, and kept the rest, sorting them into .744" - .745" and .746" - .748" groups. From a safety standpoint I think I'm fine since two of the four sources I checked say .744" is acceptable.

I know that consistent brass length is important for consistent crimp, and because 9mm headspaces on the case mouth. Then again, we're talking about 9mm here, not precision rifle ammo. Do most folks even bother going through the trouble of measuring 9mm brass, and if they do, how particular are they about using only cases that are within a thousandth or two of each other? I know I can't adjust my crimp die that finely.
 
Still going through bags of range pickup brass…

Haven’t needed to apply a crimp thus far - caution, this step induces *** heavy breathing ***

Under the impression that shorter, grossly out of spec brass headspaces on the extractor, much like how your Glock 20 manages to cycle .40 S&W ammunition.

So, not at all :rofl:
 
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I’ve never measured a 9x19 case for length. I just remove the flare and call it a day.

I do sort them and pick out stray range pick up 40 and 380 cases along with my trimmed 9x18 brass. I only use specific headstamps for Makarov conversions, but that 1 mm stands out fairly well anyway.
 
I found it necessary to sort brass by headstamp for maximum accuracy as each shoots to a slightly different POI. And oddly enough, only for my Ruger KP89, I found accuracy improved with the bullet seated out longer than recommended length. I have not found it at all necessary to measure or trim the brass. I did it once to see if it made a difference in my shooting and I couldn't tell.
 
Well, I like them to be about 19mm in length- too short and they're .380 or 9 Mak, too long and they are Bergman-Bayard, Largo, Destroyer, or Dillon.
Seriously, I still haven't even gathered everything to load 9mm yet. I still have 1000 plus .45 ACP primed and ready, and a 1000 230gr. Berry's sitting on the bench for almost a year. Been loading 12 ga. mostly, plus some .22-250 for my son.
 
With self-loading pistol cases and other types that are taper crimped, I don’t brother with trimming unless the case mouth is damaged. Or, as tmd says, if it’s cutting 9x19 down to 9x18mm.
Revolvers are a slightly different story if the case is going to be used to load a bullet that needs a roll crimp. Those I’ll spot check for consistency but I don’t care if they’re consistently long or consistently short, as long as they’re all within +/- five thousandths of each other.
HTH
 
What answer are you looking for? Cause hang on and you’re sure to find it in a day or two:)

Or are you just looking for the most common answer and will take that one? Cause I can tell you from experience, that answer has already been given—your quest is over and I’ll save you the time—don’t trim and don’t worry about length.

Back in August I started a similar thread because I wanted to begin trimming 9mm & 45ACP. I ended up not doing so in large part because of comments by @LiveLife and @Walkalong and @GeoDudeFlorida

Take a look. There are even very helpful pictures posted by @LiveLife https://www.thehighroad.org/index.php?threads/trimming-auto-pistol-cases-is-unnecessary-waste-of-time-so-that’s-what-i’m-doing.921544/

I actually ended up close to where you already are…sorting by length then loading by batches of the same or very close lengths.

Enjoy.
 
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No too picky on length but do want all to be from the same maker and lot series if possible. Don't have any guns that make bubbels in the cases so don't see much change in length from std pressure 9mm cases. Length doesn't change pressure only head and wall taper thickness does.

Have some mixed brass reloads but those get shot where finding brass is not expected so don't come back.
 
I don't mess with reloading 9mm but with .38 and .357 length plays a difference. Does it matter for 9mm, probably if your into extreme accuracy. Instead of sorting and trimming I just buy 1000 rounds of Starline and call it good. No fuss no muss and good for 8 to 10 reloads...
 
barnfrog said:
Do most folks even bother going through the trouble of measuring 9mm brass, and if they do, how particular are they about using only cases that are within a thousandth or two of each other?
Click to expand...
No. When I’m running a production run on a progressive with range brass I’m more interested in consistent primer depth, powder throw and COL. Most of my 9mm is used for USPSA and unless someone has enough data to suggest for the gun I’m using it’s worthwhile to measure and sort by length, it’s not going to happen.
 

9mm brass length - how picky are you?​

I'm not.
Headstamp? Different story for a different time, but length? Pffft! I never measure it.
You mentioned Lyman "trim-to" and "minimum" lengths as if they are the same. They're not. "Trim-to" is a suggestion. "Minimum" is usually referring to SAAMI guidelines for manufactured ammo.
 
So how does a case that head spaces on the case mouth get shorter with multiple firings? The only thing I can think of is since the case headspaces (stops) when the edge of the mouth of the case comes to a stop.... is slammed into a matching dead stop ledge machined into the chamber........it gets shorter as it is compressed over time. I may need to go back and check this, but it also seems to me that a case that starts out short after firing.....the same spent case in our bin to be reloaded.......gets a bit longer when it has been resized. When sizing, the brass has to go somewhere and it may get pushing back out the mouth. So a short fired case may not be as bad as it seems if sizing stretches it back out some.

The reason it doesn't matter much is the case is held back against the slide's receiver by the ejector. The ejector and inertia of the bullet keeps the cartridge in place when the firing pin strikes the primer, and after that, pressure expands the case to hold it in place until the bullet is spit out and pressure drops enough to release the case from the chamber sidewalls. And there is still enough pressure left to counter recoil spring and inertia of the slide to cycle the action and load another round.

At least that is what it seems like to me.
 
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Howa 9700 said:
So how does a case that head spaces on the case mouth get shorter with multiple firings? The only thing I can think of is since the case headspaces (stops) when the edge of the mouth of the case comes to a stop.... is slammed into a matching dead stop ledge machined into the chamber........it gets shorter as it is compressed over time. I may need to go back and check this, but it also seems to me that a case that starts out short after firing.....the same spent case in our bin to be reloaded.......gets a bit longer when it has been resized. When sizing, the brass has to go somewhere and it may get pushing back out the mouth. So a short fired case may not be as bad as it seems if sizing stretches it back out some.

The reason it doesn't matter much is the case is held back against the slide's receiver by the ejector. The ejector and inertia of the bullet keeps the cartridge in place when the firing pin strikes the primer, and after that, pressure expands the case to hold it in place until the bullet is spit out and pressure drops enough to release the case from the chamber sidewalls. And there is still enough pressure left to counter recoil spring and inertia of the slide to cycle the action and load another round.

At least that is what it seems like to me.
Click to expand...
I believe they get shorter because the head hammers itself into the slide face when fired. Probably why cases fired enough times are unreadable.
 
On rimmed cases that require a roll crimp (revolver) I trim everyone of them. On Auto cases that headspace on the case mouth and get a taper crimp I don't trim any of them.
 
Not a factor here. I don't crimp it either.
Resize, neck expand. (short of the flare)
Insert bullet.
DONE.

I usually hit them with the deburr before seating bullets. Never an issue with FMJ bullets. For the price they can be purchased through RMR, there is zero reason to shoot plated, or even cast bullets... unless you enjoy doing the casting process yourself.

Bonus:
Got an email that the 10% off RMR code has been extended until New Years! As always, Free Shipping!
Code is still:
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n2omike said:
Not a factor here. I don't crimp it either.
Resize, neck expand. (short of the flare)
Insert bullet.
DONE.

I usually hit them with the deburr before seating bullets. Never an issue with FMJ bullets. For the price they can be purchased through RMR, there is zero reason to shoot plated, or even cast bullets... unless you enjoy doing the casting process yourself.

Bonus:
Got an email that the 10% off RMR code has been extended until New Years! As always, Free Shipping!
Code is still:
MERRYCHRISTMAS

Bullet Reloading Supplies | Rocky Mountain Reloading

RMR Bullets Welcometo the family Shop Now Pistol Bullets Rifle Bullets Rifle Cases Apparel In Stock Now All Categories Categories Bullets for Reloading Cases for Reloading RMR in house Bullet Casting Supplies We care about quality https://youtu.be/RXZvg45M28c Popular Choice Bullets 9mm (.355")...
www.rmrbullets.com www.rmrbullets.com
Click to expand...
That was true for me in 9mm and continues to be true in 223/556. Now if the poped out a 16x 30 cal bullet they would be a one stop shop. Please Jake 😁
 
barnfrog said:
So I'm inferring from all this that the brass will never get so short that it's unsafe to load, or it will fail (split, loose primer pocket) before it gets that short. Is that an accurate statement?
Click to expand...
I'll have to admit, I've never measured the brass I've thrown away for splits or loose primers to see if it was also "too" short. I may do that next time I load 9mm just to see.
 
CQB45ACP said:
Not sure but I believe this says differently at least regarding 45acp:

How many times can I reload 45 ACP brass? – Florida Reloading

www.floridareloading.com www.floridareloading.com
Click to expand...
Very interesting. Thanks for sharing. I would have thought the case would split at the extractor groove before the primer pocket would get that shallow.

I doubt I have any 9mm or 45acp that have been loaded a dozen or more times. I usually loose about half of whatever I shoot and just replace it with more range brass.🙂
 
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