9mm trim or not

J

Jerrymltn

Inactive
I am new to reloading and I was wondering if some of you that have been reloading for awhile can tell me if I really need to trim my 9mm brass, I want the crimp the be the same, but if they are 2 or 3 thousands different does it make that much of a problem ? It calls for .744 trim length and I have some that are .746 to .747, any info would help.
 
You may want to ask this in the reloading forum for more responses. I have reloaded a fair amount of 9mm and shot it in Glocks, S&Ws, and Berettas. Never measured or trimmed a case and have had no problems.
 
I dont trim my 9mm's, and I shoot them to failure.

I use a taper crimp instead of the standard roll type crimp.
 
Very rare that you'd have to trim any handgun brass. As long as the cases are not longer than .754"(.751" is the trim-to, not .744.) you're fine.
The .746" to .747" cases are ok too.
The taper crimp is usually more forgiving than a roll crimp(no roll crimp on 9mm. Or any case that headspaces on the mouth), but 2 or 3 thou is not enough to worry about.
 
I have never trimmed any handgun cartridge and recommend a taper crimp for any auto pistol round that is supported on the case mouth like 9mm Luger, .45 ACP, or .380 ACP.

The pressures and design of handgun cartridges don't usually cause the kind of brass "flow" we see in rifle cases, so trimming is not usually needed.

Jim
 
I pass all my brass through my calipers for a final check before loading just to weed out any 380 or 9x18 which I also load and shoot. Caliper is set at max case specs. I never seem to find any over length, and I never trim. jd
 
I pass all my brass through my calipers for a final check before loading just to weed out any 380 or 9x18
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!

Not a bad idea. Better than my mark 20/20's at discerning the different cases and faster than reading headstamps and oh yeah, as you mentioned, fool proof.

Thanks.
 
I occasionally get .380's and 9mm mixed in my brass pick ups. You can instantly tell one from the other, as you run them into the sizing die. I just segregate the oddballs and keep on going.
 
Taper is what you should use. I have older dies that give a roll crimp. You always used to have to set the die to "no crimp", and use a taper crimp die in an additional step, if you wanted that type crimp. These days, I use a set of RCBS dies that have the taper crimp in the seat die.
 
I check the lenght of brass and .744 is the shortest i go with and .754 is the max I go with.So what ever is in between is good.I found that usen the Lee Factory die works good for this.You do not have to worry about the lenght of the brass.You do not really need it use one but I found it works for me and also able to use the same rounds with cast in the tarus I have that it will not chamber one size of cast but will one just under but when I use the LFD I can use the same cast that would not chamber that it will with the use of the die for cast.
 
When I first started loading 9mm, I went several loadings without trimming, with a bunch of primarily scrounged brass. Figured I better sit down and trim them, so one night I parked myself in front of the TV with a huge bag of cases (400 or so), and a Lee hand case trimmer.

After the first 100 or so didn't need trimming, I considered quitting, but turned it in to a test. Of those 400 odd cases a grand total of 2 had any material taken off, and those were just barely over the trim to length.

Never bothered trimming 9mm cases again.
 
Only reason I can think of to ever trim pistol brass is after 5 or 6 fairly warm magnum revolver loadings and you are roll crimping into groves. I've had that with some of my .357 brass. After the 5th or 6th firing (when most would probably toss the brass anyway) I had a few pieces of brass that wouldn't let me seat the bullet to my standard depth because when I crimped it it would shave a good bit of lead from the shoulder of the crimp grove. I couldn't have deformed projectiles, and I had already decided on the seating depth that I (and my revolver) liked best, so I trimmed the offending cases. I'm on the 8th firing of that brass now. I think the next time I have to trim I will test fire a few pieces of brass to 12x loadings to see how well they hold up before trimming the whole lot up again. I'm within published loads so I'm not burning the barn doors down, but I'm pretty close to max so it is a warm loading.
 
As long as the cases are not longer than .754"(.751" is the trim-to, not .744.) you're fine.
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You must be using a Lyman manual? It says trim-to .751". But, others differ.
Speer 14 says trim-to .744".
Hornady 9th says .749".
Sierra 5th and Hodgdon 2014 both say .750".

You pays your nickel and takes your choice. Like most others, I don't measure nor trim 9mm brass anyway.
 
I agree with not needing to trim 9MM. I've loaded 9X19MM for a very long time and miked many cases and measured headspace on a number of 9MMs over the years. I have VERY rarely ever found a case as long as .754". Most are closer to .744", 9MM chambers reamed near the minimum .754" are just as rare. The average of the of the 9X19MM chambers I have measured is .761"+. I wish production chambers and cases were closer together in length, but in any case, these specs pretty much insure that any manufacturer's 9MM ammo will function in any manufacturer's pistol....
 
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