9mm rounds coming apart

M

Machineguntony

New member
I'm having a problem with my 9mm rounds coming apart in the chamber. The bullet will separate from the case, and the powder will spill, if I eject the case by racking the slide on my Sig 226.

Do 9mm cases lose tension after repeated reloading? I've reloaded these cases about 25+ times.

I had this problem about a year ago, and I seemed to solve it with a medium crimp.

The round is not too long. I tested the round, and it is not engaging the rifling.

Any thoughts? Is it time to just throw out this brass and get a new batch?
 
"The round is not too long. I tested the round, and it is not engaging the rifling."
If this is actually the case, you're saying the bullet is being thrown into the bore by the cycling of the slide????

Most of my 9mm reloads are sized so small that the base of the bullet makes a bulge in the case. Sounds like a combination of inadequate sizing and crimping and way over expanding of the case mouth.
 
Tony, the bullets are sticking in the throat of the barrel? If so you have one or two issues going on. One your bullets are to long, coal is to long or the bullets have to high/fat of an ogive for you chamber and are therefore sticking in the throat. Two, your cases are not being resized back to a small enough diameter or the are just plumb wore out, 25+ loadings? Im guessing the latter is the case. A bit of crimp will help but I dont think its the problem.

What bullet are you using?
 
Do 9mm cases lose tension after repeated reloading? I've reloaded these cases about 25+ times.

I had this problem about a year ago, and I seemed to solve it with a medium crimp.
Click to expand...

No to question one.
You answered your own question with your statement about crimp. Did you change bullet supplier. The shape of the olgive can cause problems as well as concentricity. Crimp your rounds
 
I'm with 243winxb

Get the Lee Factory Carbide Crimping die.

I got to where I use them on ALL my pistol/revolver reloading. Solves all the loose bullets and feeding problems.

This die has a carbide ring at the bottom of the die. After crimping the bullet the last act is to pull the case out of the die, that carbide ring adds a final squeeze crimp leaving the case sized to factory standards.

This is a huge benefit when loading cast bullets that are a bit over size.

Eliminates a lot of feeding problems as well as loose bullets.
 
Thanks for the help fellas.

I'll try to increase the crimp. Strange because last time this happened, it was because of too much crimp. The over crimp would cause the case to bell a little bit. I released some of the crimp and it solved the problem.

I'm using Berrys plated bullets, 115 grain. Or I use a version of the same bullet from Bullet Werks.

I'm also using a undersizing die, so it can't be that there isn't enough sizing. I shoot a lot of SMG, so it helps with the feeding process.

Also, the COAL is slightly below most specs. And I did a test to see if the bullet was engaging the rifling, and it's not.

For the life of me, I can't figure it out. Just this morning I ordered some new brass to see if it's the brass losing tension. If the new rounds don't have this problem, then it's probably the brass.
 
Well you are certainly doing your do diligence. Definitely a bit of a head scratcher.

If you put a round in the chamber will if fall right back out?
 
Troubleshooting is best done methodically. I would start with measuring the diameter of the bullets. I would measure the ID of a sized case mouth. I would try the fit, by hand, of the bullet into the case mouth (mouth/neck should be at least .002" under bullet diameter). I would back off the crimp until the round no longer passes the plunk test and add just a bit until it does (too much crimp can loosen neck tension). Lastly, I would try newer brass...:cool:
 
Brass does work harden, and lose ductility. If a Lee undersize die in combination with a case mouth expansion that does not re-expand the case neck does not work, the brass is past it's useful life or the bullet is undersized.

Have never had a 9mm bullet pull from case upon feeding, but have had .380 bullets pull slightly.
 
Hi all. I haven't posted an introductory post yet but "Nice to meet you!".

It would be interesting to see good measurements of neck I.D. after resizing and after expanding, as well as bullet diameter.

I believe you said that too much crimp caused you problems before and that sounds right. Without a crimping canelure, the bullet is squished by the crimp and it does not spring back, while the brass does so to a greater degree. Thus, some neck tension is lost.

For semi-autos I try to flare the absolute minimum possible and crimp just enough to erase the flare. While developing some 9mm loads, I recently skipped the crimp altogether after learning that the bullet would not budge on neck tension alone and the virtually imperceptible flare did not hinder function at all.

Regards, John
 
1. Did you change bullets or start a new batch? I'd measure some to make sure they are at least .355" (assuming plated or jacketed).
2. Have you tried pushing the bullet into the case in a loaded cartridge? It should not move.
3. The undersized sizing die is a good suggestion (very different from the FCD, which I assume you probably already have). It will increase neck tension as long as you don't re-stretch it too much with the neck expansion plug.
4. Check the expansion plug. It may be dirty and oversizing the case neck. You can also polish it down a bit to increase neck tension.
 
9mm bullets falling apart

I agree with random_guy (welcome to the forum!).
Crimp does almost nothing for neck tension in an auto pistol.
To much crimp will deform lead and plated bullets leading to loose neck tension.

I have found that using only enough bell to be able to balance your bullet on the case is all that is needed.
Care to seat bullets straight will also avoid problems of offset bullet bulge and having cartridges not go into battery.

9mm brass is slightly tapered, so a Lee FCD die does not crimp when pulling cartridge out of die with the carbide ring in bottom of die.
I use the Lee FCD and it will help correct SOME bullet seating problems which cause brass buldge where bullets are seated.

The carbide ring should only just kiss the brass on the way in and the crimp is applied at the top of the stroke, how much crimp is determined by how you set the die per instructions.

The best crimp for auto loader pistols is just enough crimp to remove the bell.
After all, 9mm (and most auto brass) head space off the mouth of the brass.

I have loaded 1000's of 9mm rounds using the advice I have offered here and the only time I have trouble is when I don't stay focused on the task at hand.

Personally, I shoot my 9mm and 45acp brass till I lose it or it splits :D.

Good luck!

Hope this helps.
JD
 
"The over crimp would cause the case to bell a little bit. I released some of the crimp and it solved the problem." That is generally only with "roll crimps" which shouldn't be used with 9mm anyway. Excessive taper crimping would not likely do this.
 
Welcome to the wonderful, oft confusing and frustrating world of reloading. :rolleyes:

Excessive taper crimping would not likely do this.
Click to expand...
I have to disagree. BTDT, when I first started reloading semi-auto ammo and was setting up my crimp dies. Too much taper crimp will bulge/distort cases...
 
"Too much taper crimp will bulge/distort cases..."

How so? A taper crimp forces the case inward not back toward the base as a rol crimp does.
 
Could be too much crimp or the sizing die isn't sizing down enough.

If you apply too much crimp, the bullet gets swaged down (which is rather permanent) however the brass may 'spring back' a bit, resulting in less not more neck tension

Have you pulled a bullet to see if it is 'swaged' or deformed in the crimp area?
 
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