9mm case length, how crucial?

[Mitty38]

Noticed this somewhere before, but could not find it, as goes with a lot of things lately. LOL

Ok want to get some of those 9 mm test loads done tonight or tomorrow since it's going to be 36 and rainy.
Lost my case length trimmer. Had given my 9 mm brass and 9 mm stuff away because" I ain't going to need to load for a cheap round like 9mm ".
Well got a new die set, was sure I had kept my trimmer pilot, nooooooo.
Got a bunch of range pick up and was thinking I can just measure those.....but wondering what the allowable varience would be.

 

[Brad]

It will be a very cold day in hell before I trim a 9mm case.
I use a mix of range pickups and once fired. No sorting, just deprime, wet tumble, dry and go.

 

[popper]

Just size, load and shoot.

 

[Rick]

SAMMI says . . . . (Page 27)

https://saami.org/wp-content/uploads/2019/02/ANSI-SAAMI-Z299.3-CFP-and-R-Approved-2015-12-14-Posting-Copy.pdf

 

[Ian]

I caught hell for mentioning that I trim and chamfer revolver brass.

If I had to trim .45 ACP I'd quit loading it.

 

[Mitty38]

WelI guess I have my answer.

Ian,
I trim and chamfer my .357 and 38spcl every time. Just part of the inspection process. Very seldom will the trimmer even touch. But I use a Lee factory crimp on it rolling the edge into the groove. So I like all my crimps to look-be, exactly the same. My .357,38 all fly's true so why change???

 

[CZ93X62]

9mm is a cantankerous PITA for several reasons, but you have read my wailings on these subjects previously and repeatedly. Here goes some more of my heresies that get me tossed from bulletin boards with some frequency.........

Looking through several reloading tomes, the agreed-upon case length for the 9mm Luger/Parabellum is 0.754". Some case trimmers (like my Forster system) require shorter-than-standard trimmer bases for cases this short.

One cogent reason to trim straight-wall handgun cartridge cases is to assure uniform length for uniform roll-crimping. Roll-crimping is much more a revolver thing than an autopistol kink, the ammo for the bottom-feeders being taper-crimped for the most part. I have never trimmed a 9mm case for any reason, other than to turn it into 9mm Makarov brass; most of mine (W-W, R-P, and Starline) run .750"-.752". If it ain't broke, don't fix it. I have yet to find an over-length 9mm Luger case, and I have reloaded thousands of these rounds since c. 1984.

Most 9mm pistols are not target arms--they are service-grade pistols, with a mechanical accuracy potential appropriate for service usage. As such, they don't have the ability to exploit such ticky-tack "refinements" as case length uniforming. Length variations between and within case makes isn't the caliber's major bugbear, anyway--variation in case volume and case mouth thicknesses are the larger questions. Do yourself a favor--stick to one make of case in 9mm, I am phasing out my R-P cases currently and have tossed the W-W as well.

 

[Brad]

I trimmed some revolver brass for a specific load and purpose. For general use no way.

 

[fiver]

i barely sort 9mm by head stamp.
maybe if i had a target gun from somewhere in Europe.
or could shoot a handgun worth beans.

 

[Rick]

I caught hell for mentioning that I trim and chamfer revolver brass.

Not from me you didn't. Sounds perfectly logical to me. However, extremely easy on the chamfer, just enough to remove any burs.

 

[Matt]

No don’t trim doesn’t usually headspace on the mouth anyway. “Headspace” regulated by extractor holding case to breech face in most pistols.

 

[RBHarter]

I don't trim any "ACP" class unless it is visibly long or I'm making it out of something else .

 

[358156 hp]

When I shot IHMSA silhouette many eons ago I followed the traditional route of my club (at the time), and used only matched, weight matched cases from the same lot, trimmed and chamfered in my 357 mag Contender. That same ammo was used in my Ruger Security Six for Field Pistol. Funny thing, the Ruger responded nicely to fully prepped cases, but the Contender was indifferent to them, or any other ammo for that matter, and I ended up switching to a 30/30 barrel for the Contender because 357 wouldn't shoot for me. At least it wouldn't shoot competitively for me. 357 Contenders barrels were like that. I also fully prepped cases for my 45 Colt Redhawk since I was playing with fire in those days shooting 5 shot loads in a stock Redhawk. The guy who bought the Redhawk still won't sell it back to me. I have an unfired 44 Redhawk in the safe, but can't shoot it.

 

[Mitty38]

Ye I went ahead and measured them. They are all between .745 and .750. so would be a very long time before they would ever stretch to .754.would probably split or wear out a pocket first.

 

[Matt]

Yup they’ll split or you’ll loose them first. It seems that semi-auto cases don’t grow or get shorter………

 

[Winelover]

I don't trim any pistol/revolver brass. Except, when I repurpose it. I have cut down 44 Magnum brass to 44 Special when mouths are splitting. Did the same with 44 Special, turning it into 44 Russian.

My most reloaded cartridge is the 9 mm. I have five pistols and a carbine, all are factory stock. None were throated. PITA, I don't find it so. All mine feed and fire all loads interchangeably. I'm not about to have separate loads tailored for each firearm, other than the carbine. Those are separated only for optimum accuracy.

On the subject of 9 mm brass. I load almost any brand of brass. S&B not a issue, not even with seating primers. Loaded 200+, Friday with 125 RCBS RN and 5 grains of Unique.

Yesterday, I loaded 125 rounds with Aguila 9 mm brass. That brass doesn't behave nicely with the Lyman M die..............slightly bulges the brass. Must be a tad thicker, so I used the standard RCBS expander die, that's normally reserved for plated or jacketed bullets. No bulging. Had some 20+ year old 125 RCBS RN GC that were sized to .356 diameter. They grew to .357 diameter sitting all that time. Worked out perfectly. Plus, I found a use for those undersized bullets. Will probably toss that brass, when fired. The only reason I reloaded it was that the brass was already prepped and primed, years ago. Not going to bother with that red headed step child anymore.

The 9 mm is the second cartridge I learned to load, in the mid 70's, for my Browning HP. The first cartridge, I ever loaded was the 38/357 for my Python................my very first handgun.

 

[Charles Graff]

IMHO uniform case length produces the best accuracy on 9mm loads. I do not trim, but measure the length and segregate the cases based on length and head stamp.

 

[robertbank]

It will be a very cold day in hell before I trim a 9mm case.
I use a mix of range pickups and once fired. No sorting, just deprime, wet tumble, dry and go.

This in spades. I might concede that it may depend on what you do with your reloads. The 9MM, to my knowledge would not be a cartridge destined for Olympic Free Pistol. It is primary a cartridge destined for the Military, LEO, Personal Defense, Action Shooting and Plinking market. None of those markets demand one inch accuracy or less at 100 yards.

I use range brass , seldom sort brass aside from not using S&B Brass. If there is any advantage in using sorted brass vs unsortedI have not found it. I know 45acp brass will shrink over time and i have yet to find a .45acp brass that ever measured .898 or longer, new or used. My experience with that cartridge, I shoot them until they split with some cases last beyond 16 reloads. My 9MM brass either gets lost, or splits long before I reach that number. Of reloads.

OAL of the cartridge itself is the bigger issue. Chamber length and lead can vary significantly and can have an effect on reliably.

Take Care
Merry Chrismas
Ps I reload and shoot about 10 k of 9MM per year still shooting IDPA, Steel, and plinking.

Bob

 

[Walks]

I've never trimmed auto pistol brass, except when I started to load for a S&W M1917 and roll-crimped brass until I learned it wasn't neccasary.
Now it's Taper Crimp every auto pistol case and I never check case length. Don't think I ever checked 9mm since I was about 6-7 yrs old. And Dad gave Us a hand made case length gage and a bucket of brass and left My little brother and I in a corner of the garage, keep Us out the way.

 

[Winelover]

Taper crimping is always done separately and standard operating procedure for semi auto brass around here.

I have notes indicating I have loaded S&B 9 mm commercial brass as much as 15 times. IIRC, I purchased that brass just prior to Y2K from Natchez or Mid South. I have not witnessed many 9 mm cases splitting. Most issues are with the rims getting buggered up from ejector marks and PITA to put in the shell holders.

Yesterday, I just finished up reloading all the sorted out oddball range brass that had significant quantities to make it worthwhile. I reloaded couple hundred for S&B (dated) military. BTW, didn't need to remove any primer crimp. Hundred twenty five commercial S&B and around the same number of Perfecta (made by G.F.L.) without issue. I've successfully used G.F.L. before.

I pretty much only scrap 9mm range brass that has partitions like Mag Tech.