.380 neck/case thickness

[Lariatbob]

Hey, all. I searched quite a bit, couldn't find an answer.

I have been reloading for years now. Lots of calibers, rifle and pistol.
Last year started reloading .380. Have had great success.

I have found that while expanding the case mouths while resizing approx 10% of my brass will not expand. No matter what, it will crush the case and then it's trash.
I have tried reaming the brass, polishing the expander, lubing the case, etc. to no avail.
Then I found mention the other day of the case thickness "stepping" thicker just past the seating depth.
Sure enough, on the cases I have trouble with ( I have saved them for this discovery) there is definitely a step. I just thought it was residue that had not tumbled out. I see approx .05 step. If my expander just started expanding a bit earlier, I'd be ok. I get the same result using my 9mm expander so I know it's not a defective expander.

Anyway, now that I know what the problem is, what to do about it?

Do I just force the bullets in without expanding? Do I modify an expander so it doesn't enter the brass as deep before expanding?
Anyone else found a cure?

Thanks for your ideas.
LariatBob in Colorado.:banghead:

 

[rcmodel]

Oops!

You said .380, not .308 didn't you!

What brand of cases?
What brand of dies?


rc

 

[ants]

Some humble thoughts

Not all brands have the step. I set the stepped brass aside (most are Federal) and load them differently (see last sentence).

Non-stepped 380 brass loads just like any other cartridge. In fact, with .355 XTP bullets I often don't expand the case at all. I just seat them straight into the unbelled case mouth.

Expanding the case mouth on a 380 case shortens its life considerably. If you can possibly seat the bullet with very little bell you will do your brass a favor.

To expand stepped cases, I use a 38 Super expanding die. It doesn't seem to have a problem with the step.

 

[Cajun CB]

I use RCBS dies. In order to get out of the stepped case problems, it was necessary to increase the taper of the guide part of the expander. You will see two tapers on the die. First is a guide that fits in the cartridge. The second is more aggressive. It does the actual expanding.

The first part is the taper is what needs modifying. Place the die part in something that rotates (I used a wood lathe). Use a Dremel tool with a sanding cylinder to grind the taper so that it will clear the step. Don't go wild with the grinding.