9mm case prep - trimming questions

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courtknee

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A little background first before I get to the issue I'm having. First I'm a newbie. I've read the ABC's of Reloading and the Lee Modern Reloading text. I am using a Lee Breech Lock Challenger press with Lee carbide dies. To start with I thought I would start with 9mm.

I ran into a bit of a problem with case prep with 50 once fired cartridges. First I removed the old primer and sized (or so I think) the cases using the sizing die. The primers popped out with a pleasant 'ping' sound and the die was flush with the case holder. Upon trying to trim brass, I was unable to get 70% of the cases onto the trimmer gauge past the neck - that is it would never pass the portion which is right up against the blade. Thinking I had improperly sized the cartridges I tried again but they would still not get close to the blades. The needle was definitely through the primer pocket in all cases. What am I doing wrong?

I am using a mixed set of brass from various makers. The federal brass was more likely to allow trimming while S&B and WCC would not. I am not so much concerned about accuracy at this point - just getting down the process.

thanks!

Courtknee
 
Assuming you're using the Lee trimming tool: If the needle was all the way through the flashhole and resting on the Lee (trimmer) case holder, you propably have the wrong size trimmer gauge.
never trimmed a pistol case
Click to expand...
never trimmed a 9MM case either
Click to expand...
never trimmed any handgun brass before
Click to expand...

Well, other than revolver brass, I haven't either. That said, Lyman is pretty clear that these cases that headspace off the case mouth (9mm, .40,...) Must be trimmed. I've never had any issues by not trimming, but the 'book' says to.:confused:
 
The only pistol brass I have ever trimmed was 357Mag and that's because of the roll crimp.

I never trim 380, 9mm, 40, 45acp..... You get the idea. Not needed with most all straight wall brass using the Taper Crimp.
 
It sounds like they are below trim length. The needle is bottoming out before they get trimmed, so they don't need trimming.

I am with the "never trim handgun brass" crowd also.
 
I agree that it sounds like the cases are less than trim length and therefore nothing to worry about.

There is a maximum trim length, just like any cartridge case. For 9mm luger it's 0.754". I just processed a batch of around 500 cases, and I do measure them all. Out of that 500 I ended up trimming only around 30 cases. It gives me some peace of mind, in the same way that being careful about powder charge and OAL gives me some peace of mind.

There's a max case length for a reason, I suppose it's up to each end user to decide whether to arbitrarily ignore load specs.
 
Did you run them thru the expander die before you trimmed? If not that is your problem.
 
Generally, I do not trim handgun cases. 25 years or so ago I had this great idea of making all my 357 Mag brass the same length. The trimmer I had at the time was not up to the task. So I stopped. But, I do have several boxes of new brass, trimmed, ready to load 357 Mag brass on hand.

My 38/45 Clerke brass gets trimmed in the forming process. It has a trim die. After forming, I have not trimmed any since.

I did buy a 9x19 trim die and extended shell holder with the intent of trimming and making uniform some 9x19 brass. I have not used the die yet after a couple of years.

I also have Lee trimmer systems for 9x19 and 38 Super. Again, they have jot been used. In fact, the packages have not been opened.

So, I guess I agree with others, why bother trimming handgun brass.

Of course, I get anal about some aspects of reloading so I guess some might get that way about trimming handgun brass. If it rings your bell, go for it.
 
My guess would be that your dies are not sizing the case enough. The 9mm has a tapered case. Hence, the more you size the longer the case gets. Most dies do not return the case to original dimensions. Lee makes an undersize die that sizes the case more and will most likely enable you to get them through your trim gauge. With that said, please don't trim your 9mm brass uless it is longer than .755". 99.9% of your cases will not even approach .755". Most will be under .750". You will be better off sorting them by lenght, and culling those which are under .745".
 
Reload the same case over a long period of time and you'll probably find that the brass actually shrinks rather than grow in length. I don't know why this happens but it does. I too have never trimmed a single piece of pistol brass in 40 years plus of reloading.
 
Straight walled pistol brass doesn't generally stretch the same way that bottle neck rifle brass does, so is generally not nessasary to trim straight walled pistol brass. If this isnt 9mm brass that you personally have fired, then verify somebody else hasn't trimmed it down to 18mm to reload 9mm Makarov. If they have then obviously it's no longer suitable for 9x19. Also if these are pickups that you didn't fire, make sure they are not .380, sometimes 380 is headstamped "9mm Br" and factory Makarov brass is sometimes stamped "9mm M". That could explaine why your cutter isn't reaching your brass.
 
Had a similar incident last week with Lee dies and a RCBS trimmer. Turned out the case mouth was too small for the pilot. Finally I said the hell with it and loaded them anyway. They shot fine.
 
There is quite a difference of opinion on whether or not to take the time to measure and trim 9mm brass. On what I have read most folks who reload say they don't "waste" time doing it, just reload as is. As we all know, case length on rimless cartridges directly effects correct headspacing.
Well after doing a little experiment of my own I have found that finding the correct case lenght for your pistol might make a large improvement in accuracy... at least it did in mine and my brother's BHP's. Although I do not have a Ransom I did use suitable rest for this purpose, making sure POA was as close to exactly the same on all shots that these old eyes could do. It didn't take long to find where the sweet spot was. With case lengths between .746" and .750", it was very easy to see the effects on the grouping. The closer I got, the tighter the groups became.

This is the final result. Even factory WWB did not do near this well. Needless to say that I'll be taking a little more time in 9mm case prep, maybe not so much in trimming since most autoload case tend to get shorter, but I will at least cull out the ones that are too short.

I have also observed that factory WWB brass is consistanly shorter that factory Remington brass. In some cases it is shorter than the recomended trim length. Have you ever had a pistol that seems shoots better groups with ammo over another? This might be the reason why!

Just thought I'd pass this along.
 

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i can not tell you how many tens of thousands i have reloaded. i check through the pistol brass every winter, and i have trimmed 3 cases in all of that. forget about trimming, and go shoot!
 
I think I have trimmed a dozen 9mm cases over the years, and that is with the cutter just barely "kissing" the brass and not really doing much cutting.

I have 9mm I have fired and reloaded so many times you can barely read what brand it is anymore on the headstamp.

I think you will wear out primer pockets long before the need to trim 9mm.
 
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