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Case length inconsistent

4K views 12 replies 11 participants last post by  sharps4590 
#1 ·
I did a search of the forums before I posted this. I seen lots of post on varying OAL but nothing on varying lengths of cases of 9mm. I know cases vary and that is normal(manufacturer, amount of reloads, pressure, etc)but what I am finding hard to understand is this. I recently started reloading 9mm Luger and found during the reload process is that the case lengths vary from BELOW minimum to just short of trim length. All these cases new factory, fired in the same gun, and all were from different manufacturers. Since 9mm headspaces off the mouth of the cases, shouldn't their length be between trim length and maximum length. I've been loading rifle cases all my life and I pay close attention to cases length and trim amounts so I can get the most use out of a case but to also know when to discard because of thinning and trimmings. So, any input would be appreciated.
 
#2 ·
I have found that you do not need to trim 9mm brass. I have never actually measured a 9mm case, I just load them and have never had a problem with them at all. I just opened my Hornady manual to see what the length is supposed to be, it shows .754 as Max OAL and the trim to length is .749. Yes I would guess that the length should be between those two. I would venture to say that you shouldn't have any problems with them unless you are WAY off on the length.

I assume that you know that there are more than one type of 9mm. The standard 9mm is 9x19 (Luger), there is a 9x18 (Makarov) and a 9X21 (Largo).

I will say once again, you do not need to trim 9mm, for that matter, I have never trimmed handgun brass of any kind.
 
#3 ·
I have never measured 9mm case length, oh, I guess I do when I separate 380 from 9mm, but I have never trimmed a pistol case, nor do I worry much about case length. Maybe I should, but if it plunks, it loads...(my plunk test is a 9 mm cylinder for my Blackhawk)
 
#4 ·
Firing handgun cartridges rarely stretch the brass like a bottle necked case does. Most often length change comes from sizing, which will some times lengthen the case, but not always. I am one of those that haven't measured a 9mm case in mebbe 12 years, and 45 ACP brass in 18 years. I give all my semi-auto reloads the "plunk test" and have never had a problem with my reloads firing...
 
#5 ·
ok... after reading these past 3 posts, which I really appreciate the input, I'm getting that I need to watch out for case separation even more so than stretch/trimming of the case. I have recently seen some really great pictures on what to look for on case separation on this forum(thank you again to them). I seem to be getting kinda techincal but I have had a double loaded case in a rifle go off in my face many years ago. Its one of those things that stick with you :).
 
#6 ·
The typical case failure would be split necks. In over 25 years of shooting several different pistol rounds I have never had or even seen a case head separation. The exception might be from a round fired out of battery (slide not fully closed) in which case the side blows out. But that can be catastrophic as a recent video for a SPW M&P in 9mm that fired a bad re-manufactured round (probably overloaded accidentally) with the slide not full closed which apparently that gun is know to do.

I too do not trim any pistol brass that uses straight walled cases.


LDBennett
 
#7 ·
So the bottom line is not to worry to much about length unless it is noticeably shorter and not to worry about stretch because the necks will crack long before then. Got it. Like I said, new at pistols and wanting to get a base line to work from.
 
#10 ·
I too do not measure or trim my .380acp, 9mm, 40S&W or .45acp cases. But I do put my .38spl., .357mag., and .45 Colt cases through the trim phase one time when I first get them. I know it is not necessary but when the snow is deep and temperatures are cold and I am house bound, I trim them only so I can get a consistent roll crimp. It is just a one time thing and I am anal.
 
#11 ·
What follows is a description of what I choose to do with my pistol brass. In no way am I claiming to be an expert or disparaging the methods of others that differ from mine.

I have a .357 Magnum trimmer because some of my well-used brass was actually over the max length. In other cases the mouth was a little ragged from multiple reloadings and a quick trim cleaned it up a bit. I have a .38 Special trimmer because some of the .357 Magnum cases mouths were chipped deeper than the trim length for .357 so they became .38 brass. I do also value equal case length on my .357 brass so that I know my H110 loads all get a good roll crimp on them. Light 38 Special loads with plated bullets - not so much.

I don't yet have a trimmer f0r .40S&W, but after having just completed resizing over 1500 pieces of range brass I am confident in saying that while some manufacturer's brass is slightly under typical trim length some are within about 0.002" of max length and may need trimmed at some point. I'm a little lax with my 38/357 loads, but each semi-auto case must fit into an L.E. Wilson case gauge after re-sizing and it is checked again after the load is completed. If a loaded round won't fit the gauge it indicates insufficient taper crimp which I'd rather find on the reloading bench than in the field. My chambers are a lot sloppier than the case gauge so it ensures that every round will chamber and headspace correctly while not missing any finer details such as a light crimp.

I guess I find motivation to trim my pistol brass in the notion that it shows great care and attention to detail in attempting to make a product that meets or exceeds the quality of factory loads.
 
#12 ·
What follows is a description of what I choose to do with my pistol brass. In no way am I claiming to be an expert or disparaging the methods of others that differ from mine.

I have a .357 Magnum trimmer because some of my well-used brass was actually over the max length. In other cases the mouth was a little ragged from multiple reloadings and a quick trim cleaned it up a bit. I have a .38 Special trimmer because some of the .357 Magnum cases mouths were chipped deeper than the trim length for .357 so they became .38 brass. I do also value equal case length on my .357 brass so that I know my H110 loads all get a good roll crimp on them. Light 38 Special loads with plated bullets - not so much.

I don't yet have a trimmer f0r .40S&W, but after having just completed resizing over 1500 pieces of range brass I am confident in saying that while some manufacturer's brass is slightly under typical trim length some are within about 0.002" of max length and may need trimmed at some point. I'm a little lax with my 38/357 loads, but each semi-auto case must fit into an L.E. Wilson case gauge after re-sizing and it is checked again after the load is completed. If a loaded round won't fit the gauge it indicates insufficient taper crimp which I'd rather find on the reloading bench than in the field. My chambers are a lot sloppier than the case gauge so it ensures that every round will chamber and headspace correctly while not missing any finer details such as a light crimp.

I guess I find motivation to trim my pistol brass in the notion that it shows great care and attention to detail in attempting to make a product that meets or exceeds the quality of factory loads.
I havent had to trim any 9mm but I do measure the cases and try to separate my cases into two groups . Federal cases seem to be around.747 + or - .001 and my Winchester seemed to be around .750 +or- .001. I haven’t noticed any difference on how they shoot except for having to reset my tampered crimp for each size and i am not sure if the difference has a noticeable change in the crimp, but I have taken some apart with berry rn bullets and found scared marks on the longer cases when crimp was set on a short case,
 
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