Wrinkled 9mm cases

[Dmath]

This has just recently started to happen. I'm loading 9mm on my RCBS press, using a variety of brass (range pickup, but mostly my own) and standard RN FMJ 115-grain bullets. Even though I have the expander plug most of the way down inside the case, and the case mouth is clearly belled, it seems to require excessive force to load the bullets. About one in three cases winds up wrinkled. (And yes, if anybody is wondering, the body of the expander die is all the way down and just touching the shell holder when the ram is at the top of its stroke.)

Two questions:

1. Anybody have an idea what's causing this?

2. Is it unsafe to go ahead and shoot this stuff, thus fire-forming the cases?

 

[BYJO4]

First, you have your expander going to far into the case and I'm sure you are over expanding. All you want is just enough to start the bullet into the case. With you particular problem, I would first mic the bullets you are using to see if they are over size as 9MM FMJ will normally seat easily and with almost no expansion of case mouth. You also need to check case diameter to make sure the sizer die is correctly sizing the case. You might also want to post a pic so we can see exactly the situation.

 

[Reinz]

Yes, a pic of your full length expanded case would be nice to see.

That's a heap of work for the crimp die.

 

[WestKentucky]

Sounds like your crimp is not properly adjusted as much as anything. If you are crimping before seating it causes the case to crumple like a soda can as it tries to keep seating a bullet after it is crimped. Like this...these are 30-30 but I have done the same with others too.

 

[Reinz]

That makes perfect sense WK.

 

[Schwing]

Are you seating and crimping at the same time? Like Westkentucky said, if it starts crimping and the bullet is not yet completely seated, it basically crushes the case. If you do seat and crimp at the same time, you need to make sure that the bullet has been seated so that the top of the case is almost directly in the middle of the cannelure. This way, when the bullet is crimped, it still has a few thousands room left to complete seating if it hasn't done that before the crimping starts. If the top of the case hits the end of the cannelure and is still being seated, it crushes the case instead.

 

[Dmath]

Okay, thanks. I will go back off both the expander and crimper-seater dies and start all over. Excessive crimp had not occurred to me. . . . which shows the value of posting on here.

 

[Dmath]

Thanks and thanks again!

Crimping was the problem. I went back and started all over and now the bullets seat just the way they used to.

The origin of the problem was that I moved into this house three years ago, and I have loaded mostly other calibers since then. The 9 mm dies had lost their zero, so to speak. But focusing on the crimp was the key.

 

[Dmath]

But the question remains: Can I safely shoot the wrinkled cases? And, for that matter, the other cases that didn't wrinkle but that required an unusual amount of force to seat/crimp?

 

[IMtheNRA]

Post a picture of the cases in question, otherwise we're just guessing what "wrinkled cases" means.

 

[FROGO207]

Something else to throw into the mix is some of the newer brass have an internal step to keep the shorter bullets from sliding into the case. If a longer bullet is used the case can bulge or accordion down or both. I have seen this in 380 and 9MM casings so far.

 

[FROGO207]

Something else to throw into the mix is some of the newer brass have an internal step to keep the shorter bullets from sliding into the case. If a longer bullet is used the case can bulge or accordion down or both. I have seen this in 380 and 9MM casings so far.

 

[hartcreek]

Without photos any advice is useless. Photos of howm much you are belling the casemouths cuz it only takes a little bit and a photo of the wrinkled case.

AND yes you can seat the bullet and crimp at the same time. I do it all the time and with 9mm using a roll crimp.

 

[loose noose]

hartcreek, I do believe you mean a taper crimp, not a roll crimp on 9mm.

 

[herkyguy]

I did this when I first started reloading due to not backing out the taper crimp enough.

On some .308 I loaded, there was a very slight "wrinkle" at the neck and it shot just fine (also expanded the brass back to how it should look minus the wrinkle) but it loaded very tight.

I chucked some .357 with the same problem because the cartridge was excessively buckled.