Case Trim Length

[Mals9]

My Lyman 49th manual calls the trim to length of 9mm Luger at .751" but many of my once fired Winchester and Blazer cases are measuring in at .743" and up. The manual says "The cartridge headspaces from the mouth and therefor case trimming must be uniform and accurate. Do not reduce cases below the trim to length." Are there any inherent issues with the shorter cases? I am new to pistol reloading and trying to learn.
Thanks

Mals

 

[patrickd]

I've been picking up 9mm range brass for upwards of 30 years, never once bothered to trim any of it , loaded 10's of thousands of rounds of it, all with range or my own once fired brass with nary a problem. I'm sure many people will tell you I probably should've, but at this point if any issues haven't occurred, I'm not about to start. In my experience, straight walled pistol cases don't tend to grow like bottle necked cases do.

 

[robertrwalsh]

An overly short case will end up headspacing on the extractor hook and not the chamber. That will tend to hold the case slightly cockeyed and MIGHT contribute to decreased accuracy. That being said I once put a whole box of .380 thru a 9mm just to check. I had to manually cycle the slide as the .380 did not have enough oomph to do it, but the bullet came out the end of the bore every time and accuracy wasn't unreasonably poor. Also if the case is way too short the bullet maybe won't grab properly and can come out when the slide slams the round home. That can be a bad thing. All that being said I don't remember the last time I trimmed a 9mm case to length, at least since I was making my own Makarov brass.

 

[9mmsubgun-m11]

Having loaded 100,000 plus 9mm for pistol,smg,revolver and rifle use I have never trimmed one.Some of the cases I have loaded upwards of 50x. Have never trimmed a pistol/revolver case.

 

[fredj338]

Headspace is on the case mouth, but often the the case is held in place by the extractor. Its only an issue if the cases get too long, & that never happens.

 

[BLUEDOT37]

My Lyman 49th manual calls the trim to length of 9mm Luger at .751" but many of my once fired Winchester and Blazer cases are measuring in at .743" and up.

To specifically answer the length question, the SAAMI max. length is .754". The minimum length is .744" (-.010") The typical trim length is in the middle, .749" (-.005"). Don't worry about .743" cases.

The headspacing issue has already been stated. Now go reload.

.

 

[Mals9]

Thank you very much for the replies. I am sure I am overthinking this.

Mals

 

[forestswin]

Mals9
Are you measuring case lengths after resizing?

Cases should be measured after resizing.

 

[BE Mike]

Having loaded 100,000 plus 9mm for pistol,smg,revolver and rifle use I have never trimmed one.Some of the cases I have loaded upwards of 50x. Have never trimmed a pistol/revolver case.

I've loaded 100,001 plus straight walled pistol cases and never trimmed them. Sorry, I just had to one up you!

 

[Sportsdad60]

Thank you very much for the replies. I am sure I am overthinking this.

Mals

It's normal to overthink and have extremely high quality standards when you're new to reloading. It's a good habit to be in awareness mode and research each cartridge before reloading. After your comfortable, you get to know what is considered acceptable and what is not, both in your own quality standards and those that the books preach. Like many of us, you should document each load and find your favorites. Then it's less research time the next time you load a particular caliber. I'm up to 9 calibers that I reload for now (After 1 year of reloading) and each it thoroughly documented as to what was the best (OAL, Powder charge, Primer type, bullet type etc)
It sure is a fun hobby using science!

 

[H Richard]

I have never trimmed a 9mm or 45 acp case in over 30+ years of loading. I have trimmed some 38 Special back when I was loading for my Mod 52 for match accuracy, but it was just for a few special matches. My rifle brass gets measured and trimmed.

 

[rwsmith]

If they fired in your gun...

If they fired in your gun one time there's no reason not to reload them and shoot them again. Saves the trouble of trimming. I don't believe that I have trimmed any pistol brass.

 

[AveragEd]

Nor have I although I did return some new Winchester brass in 7mm STW that had very short necks that were cut off at an angle. As rwsmith indicated, if the brass shot properly once, it should do so again.

Ed

 

[gwpercle]

In 9 mm Luger the short answer is NO.
Only trim 9mm if they reach 0.754' , then you can trim them back to 0.749' or 0.750' . It's not that critical.
For some reason the 0.743' cases reload and shoot just fine.

Let me pass on a hint I learned , don't bother measuring and trimming 9 mm or 45 acp , just sweep them up and reload them, all the measuring, sorting by length and head stamp really does no good for ammo shot informally at under 25 yards...unless you're shooting for money.
The targets I have shot at 25 yards do not show any better accuracy between trimmed and sorted cases and mixed cases untrimmed ....exact same bullet and powder charge....I would have never believed it , I would have bet money that sorted and trimmed cases were more accurate.....they are not.
Or at best they might be marginally more accurate....but not enough to go through all that trouble.
Anyone else conduct a test like this. Rifle ammo is another story.
Gary

 

[ageingstudent]

In 9 mm Luger the short answer is NO.
Only trim 9mm if they reach 0.754' , then you can trim them back to 0.749' or 0.750' . It's not that critical.
For some reason the 0.743' cases reload and shoot just fine.

Let me pass on a hint I learned , don't bother measuring and trimming 9 mm or 45 acp , just sweep them up and reload them, all the measuring, sorting by length and head stamp really does no good for ammo shot informally at under 25 yards...unless you're shooting for money.
The targets I have shot at 25 yards do not show any better accuracy between trimmed and sorted cases and mixed cases untrimmed ....exact same bullet and powder charge....I would have never believed it , I would have bet money that sorted and trimmed cases were more accurate.....they are not.
Or at best they might be marginally more accurate....but not enough to go through all that trouble.
Anyone else conduct a test like this. Rifle ammo is another story.
Gary

I did. I trimmed 100 .40 S&W cases for consistency and cleaned the primer pockets and compared them against 100 random length with uncleaned primer pockets. I shot 50 each at 25 and 50 yards from my P226 from a rest. I did not detect a noticeable difference.

 

[Wise_A]

I've not trimmed, though I have sorted.

If you're not shooting a formal precision competition like bullseye, it is genuinely not worth the effort. Case length will commonly be all over the map. 9mm probably more so than many others.

 

[ChiefStealth]

Thank you very much for the replies. I am sure I am overthinking this.

Mals

It is reloading law that you must have a special log for keeping track of all of the things that you overthink, overreact, overlook, etc... The log must also document all of the stupid mistakes you make along the way. So, years from now you can read through the log and laugh at yourself.

 

[Eddie Southgate]

In 9 mm Luger the short answer is NO.
Only trim 9mm if they reach 0.754' , then you can trim them back to 0.749' or 0.750' . It's not that critical.
For some reason the 0.743' cases reload and shoot just fine.

Let me pass on a hint I learned , don't bother measuring and trimming 9 mm or 45 acp , just sweep them up and reload them, all the measuring, sorting by length and head stamp really does no good for ammo shot informally at under 25 yards...unless you're shooting for money.
The targets I have shot at 25 yards do not show any better accuracy between trimmed and sorted cases and mixed cases untrimmed ....exact same bullet and powder charge....I would have never believed it , I would have bet money that sorted and trimmed cases were more accurate.....they are not.
Or at best they might be marginally more accurate....but not enough to go through all that trouble.
Anyone else conduct a test like this. Rifle ammo is another story.
Gary

I have and what I determined was that I am not accurate enough to tell a difference in sorted or unsorted cases in a handgun. I still think all ( rifle & pistol ) cases should be sorted by brand and
I load each box of cases as a unit so every case in the box has an equal number of loadings. That's the way Elmer did it ,that's the way my grandfather did it , and that's the way I still do it.

Rifle cases I can tell a noticeable difference in . I shoot a lot of 7.62x54R in Finnish Nagants and have a pet load that I worked up in S & B cases because that was the only cases that I had available at the time that were reloadable. I later purchased a large lot of Privi brass from Graf & Son and found that the same extremely accurate load did not work in these Privi cases . There was a noticeable difference in case volume between the two brands. I never mix rifle cases and would be very hesitant to mix pistol cases if working up anything like a max load.

Just my 2 cents, your mileage may vary.

Eddie
P.S. As of yesterday Graf had 135 gr Gold Dot SB's in stock .

 

[fredj338]

It's normal to overthink and have extremely high quality standards when you're new to reloading. It's a good habit to be in awareness mode and research each cartridge before reloading. After your comfortable, you get to know what is considered acceptable and what is not, both in your own quality standards and those that the books preach. Like many of us, you should document each load and find your favorites. Then it's less research time the next time you load a particular caliber. I'm up to 9 calibers that I reload for now (After 1 year of reloading) and each it thoroughly documented as to what was the best (OAL, Powder charge, Primer type, bullet type etc)
It sure is a fun hobby using science!

I assume this is always the case & in my class I reinforce the importance of good records for your handloads. Nothing worse than having a good load or bad load & then not having the data for it.

 

[fredj338]

I've not trimmed, though I have sorted.

If you're not shooting a formal precision competition like bullseye, it is genuinely not worth the effort. Case length will commonly be all over the map. 9mm probably more so than many others.

Unless you can handhold sub 2" groups at 25yds, sorting brass won't be a detectable variable IMO. Even then, most would be hard pressed to determine an accuracy advantage. If yo ucan do 2" or better, then you might just be able to tell sorted once fired from range pickups, maybe.