Case bulging after crimping

[alanwk]

Its been a while since I reloaded ammo. So be gentle . I have had this happen a few times today. After sizing my 9mm cases, the brass fits nicely in a case gage and barrel. But after seating bullet and crimping they will not seat in my gage. Any an all help is appreciated. Thanks.
Alan

 

[lonestardiver]

What for of crimping are you doing?
If any, it should be a light taper crimp due to how the case headspaces.

Have you made any measurements in diameter before and after to determine where dimensions are off?

 

[Txhillbilly]

Sounds like you're over crimping the case. Back off the crimp until the bulge is gone and you should be OK.

 

[usmcpmi]

What dia. bullet? Does sound like the seating die needs to be backed off a little.

Sent from my SM-A125U1 using Tapatalk

 

[alanwk]

What for of crimping are you doing?
If any, it should be a light taper crimp due to how the case headspaces.

Have you made any measurements in diameter before and after to determine where dimensions are off?

No I have not. Didn't think of it. But I will look into it. Thanks for your quick reply

 

[usmcpmi]

Might check your case length...

Sent from my SM-A125U1 using Tapatalk

 

[Deavis]

Assuming you solved your issue but if you haven't, you need to set your taper crimp using your calipers. Forget all the talk about slight taper, straightening, eyeballing, etc. There are reference dimensions for your cartridge mouth and all you have to do is measure to make sure you are meeting them. A good taper crimp on 9mm will be about .375-.379 at the mouth of the casing, which is a few thou less than the SAAMI cartridge max and will provide positive feeding across brands of brass. Simply turn down your die until your mouth measures in that range for your mouth, lock your die, and move on. Remember different brands of brass have different thicknesses so you'll see variation due to spring back but your calipers and the SAAMI drawing are your best friend. If your mouth is in that range after crimp and you have a bulge beneath it then you have another issue with your setup.

 

[alanwk]

Assuming you solved your issue but if you haven't, you need to set your taper crimp using your calipers. Forget all the talk about slight taper, straightening, eyeballing, etc. There are reference dimensions for your cartridge mouth and all you have to do is measure to make sure you are meeting them. A good taper crimp on 9mm will be about .375-.379 at the mouth of the casing, which is a few thou less than the SAAMI cartridge max and will provide positive feeding across brands of brass. Simply turn down your die until your mouth measures in that range for your mouth, lock your die, and move on. Remember different brands of brass have different thicknesses so you'll see variation due to spring back but your calipers and the SAAMI drawing are your best friend. If your mouth is in that range after crimp and you have a bulge beneath it then you have another issue with your setup.

Thank you for this information. I needed that.

 

[TexMex247]

The Lee FCD is the way to go with semi auto cartridges. Never had any chambering issues using them.

 

[paknheat]

The Lee FCD is the way to go with semi auto cartridges. Never had any chambering issues using them.

Agreed, been using them for years now.

Got one for every cartridge I load for that requires crimping.


Sent from my iPhone using Tapatalk Pro

 

[S13]

Assuming you solved your issue but if you haven't, you need to set your taper crimp using your calipers. Forget all the talk about slight taper, straightening, eyeballing, etc. There are reference dimensions for your cartridge mouth and all you have to do is measure to make sure you are meeting them. A good taper crimp on 9mm will be about .375-.379 at the mouth of the casing, which is a few thou less than the SAAMI cartridge max and will provide positive feeding across brands of brass. Simply turn down your die until your mouth measures in that range for your mouth, lock your die, and move on. Remember different brands of brass have different thicknesses so you'll see variation due to spring back but your calipers and the SAAMI drawing are your best friend. If your mouth is in that range after crimp and you have a bulge beneath it then you have another issue with your setup.

This is the answer.

 

[Deavis]

The Lee FCD is the way to go with semi auto cartridges. Never had any chambering issues using them.

That's because they iron out any mistakes made before getting there and can give you a false sense of security about the quality of your techniques or components. That's not to say they aren't useful or even a great tool when used for the right reasons but just realize that they can cover up sloppy work in front of them. They are not the answer for people having setup or process problems with their reloading setup, they are a crutch to avoid fixing the real issue(s) facing a reloader.

For this poster, his issue appears to be setting up his die to deliver a proper taper crimp. You can crimp until the case bulges and the FCD will happily iron it out on the way up but that isn't the best solution. Especially since that would destroy the neck tension you worked so hard to get. In my opinion, there is nothing superior about the crimp delivered by the Lee pistol FCDs when compared to most other brands out there for the normal reloader.