Need help with .40cal pistol brass problem

Keebler750

Keebler750

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I first have to admit to poor reloading practices when it comes to pistol. Unlike all the prep I do for rifle, with the 40 S&W I just tumble them, and run them back through the Dillon 550 with Dillon dies.

I have about 800 pieces of brass, some once fired, some unknown vintage, all mixed together. I have probably put 2500 reloads through my Sig, plus some factory ammo.

I just started noticing a weird line at the start of the case head after making some rounds up. This is only happening on a small percentage of the reloads, not all. The body brass is shiny, the body is 'coke bottled' (which I've been told is normal for Dillon resizing), and there is a line or sharp ridge about 1.5 - 2mm above the bottom groove on the case head. I am trying to figure out the cause, and cure.

I sorted my completed rounds so I don't shoot these. They appear ready to come apart at what MUST now be a stress riser.

I checked my dies and cleaned them. No obvious problems.

I just looked up the .40 data, and realized I should be trimming???? So I measured all my clean brass and it is way UNDERSIZE. Even the once fired. The book says it should be 0.845" 'trim-to' and my avg. is 0.836". The mouth sets the headspace, too.

I need someone to set me straight here!! I will take the rounds and show them to someone at the range, but what do you guys think???
 
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You mention that your brass is mixed.
Are the reloads that you are having the problems with also mixed makes or is it one particular make ?
If not perhaps the reloads came from one gun that did a number on the brass ??

Usually ( Not always ) there is a common factor when there is a problem.
 
I just checked.

The brass is mixed manufacture.

The problem with this is none of the clean brass shows this issue ... until AFTER I make the cartridge, therefore I can't sort them out of the rotation.

Ugh! I guess I need to go to new brass to check this one.
 
The 40s&w is a high pressure cartridge therefore you will only be able to "safely" reload a given cartridge only so many times. Compare this to the 45ACP which can be reloaded more times because it is a low pressure cartridge.

In order to know which brass should be "retired" you must not mix your once fired brass with your twice fired, etc. and should judiciously keep track of your "lots". You must also inspect each case before reloading!

Some 40s&w barrels provide only marginal case support in the head area and stress lines are quickly followed by blowouts!

If your press is properly adjusted you can't do much more about the resizing die except try a different make. Get rid of any questionable cases immediately!
 
Well, at least I was smart enough to pick up on the problem before firing them!!

I was told pistol cases practically lasted indefinitely. I've gotta learn to take 'experts' with a grain of salt.
 
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I've had the odd 40s&w do the same
I use a RCBS carbide sizing die
My thought was the case was not quite straight entering the die,a little Dillon case lube added to the case tray seemed to make the problem go away
 
I've had the odd 40s&w do the same
I use a RCBS carbide sizing die & a Dillion 550
My thought was the case was not quite straight entering the die,a little Dillon case lube added to the case tray seemed to make the problem go away
make sure the shell plate is clean,a can of compressed air froma electronics store is great
 
it's like anything else-LOW PRESSURE cases will last almost indefinately- start loading 'MAGNUM" - high pressure loads and it shortens case life- this should be in the reference section of your reloading manual- mine is, and i KNOW IT'S in the lyman
 
t-star said:
it's like anything else-LOW PRESSURE cases will last almost indefinately- start loading 'MAGNUM" - high pressure loads and it shortens case life- this should be in the reference section of your reloading manual- mine is, and i KNOW IT'S in the lyman
Click to expand...
There's books on this?:p:p
 
brass oal

are you measuring your brass before you size it???? this would explain why it is so short. The brass will be longer after resizing it. It sounds like your ring around the base is where the case is solid and the working of the thinner brass has left the ring, much as you see with rifle brass after the third or fourth reload. This is the first sign of thinning and in your case with a forty is time to consider all new brass due to the fact you have mixed it.
 
If you are using a dillon die, it does not size the brass all the way to the base. Most people who I know that shoot 40 for competition or otherwise will substitute in the EGW U die due to it being able to size the cartridge all the way down to the shell plate. The Dillon die is tapered at the botton to aide in processing on the progressive press. I have a 650 and I put the EGW U die in station 2 and move my powder drop to station 3, seat to 4, and crimp to 5. I use the regular Dillon deprime on 1. The EGW U die is cranked all the way down and this will size the brass a bit farther down than the standard Dillon die will. I think it's about $20 or so. Since you have a 550, you may need to substitute the EGW U die for the Dillon deprime die. It will do the same thing. I fire my 40's ina Sig 229, a Para P16, and a Model 610 classic. They all go through the U die.
 
Post a picture of the problem brass in order for us to see what you are trying to tell us.

Trimming the brass:
I have loaded 10-thousands of 40 SWs and NEVER trimmed a single brass. You dont need to trim them.

U-die for a stock SIG bbl:
You dont necessarily need a "U-die" to reload for a SIG bbl unless you have replaced the bbl with a tight match barrel. The Lee factory crimp die will do the job perfectly without undersizing your rounds.
Replace the Dillon die on your 4th station with Lee factory crimp die.

Good luck and Reload safely :)
 
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