Reloading 380ACP. Um, Help Please?

[dleong]

I am in the process of reloading my first batch of 380ACP cartridges for my recently-acquired Bersa Thunder 380.

I am using brass from a 100-round box of WWB 95 gr. 380ACP ammo that I had previously fired through the gun to break it in (the Thunder 380 is surprisingly accurate, by the way!); projectiles are Berry's 100 gr. 380ACP RNHB with a measured diameter of 0.356", and the dies are by Lee.

Here is the problem: the resized cases do not seem to have enough neck tension to hold the projectile securely in place prior to the crimp being applied. Comparatively little pressure is required on the press when seating the projectile, and when I perform the neck tension test by pressing the uncrimped cartridge against a hard surface, the projectile quite easily sets back into the case. When a moderately heavy taper crimp is applied, the projectile resists setback a little better.

Is this lack of neck tension normal for a resized 380ACP case? I have reloaded thousands of cartridges in other calibers, and have never run into this situation. The neck of the resized case has an OD of 0.368", and I have the resizer die set up so that the shellplate just makes contact with the bottom of the die when the ram is at the top of its stroke (as per the instructions). Should I be doing something differently?

Any advice or suggestions are welcome. Thanks in advance.


DL

 

[R.W.Dale]

In your case your problem sounds like you've gotten hold of a funky set of dies.

MY Lee 7.7jap dies do the same thing. I've had to start using my RCBS 7.62x54r die FL to size the neck down enough to get the case to hold onto a bullet.

 

[marlin.357]

Just for grins

You shouldn't be able to push the bullets back into the case, but sounds like you are doing everything right.

Just for grins what is the insde diameter of the case neck, would expect it to be .354-.355.

I know someone who tried to use 9mm dies to resize .380 brass, bullets would slide in with almost no pressure.

 

[dleong]

Just for grins what is the insde diameter of the case neck, would expect it to be .354-.355.

D'oh! If I had been smart, I would have measured it. As it is, I've reloaded all of my available 380ACP cases. I put a moderate crimp on them, so the projectiles should stay in place, at least through a single chambering for my initial round of chrono tests.

I know someone who tried to use 9mm dies to resize .380 brass, bullets would slide in with almost no pressure.

Tried that, doesn't work. The 9mm is a tapered cartridge, and a 380ACP case doesn't go high enough into the die to properly resize the neck.

 

[marlin.357]

Should

"I put a moderate crimp on them, so the projectiles should stay in place, at least through a single chambering for my initial round of chrono tests."

Well, should and will are somtimes different things. Try cycling a few through without firing to see if feeding sets them back in the case. If it does you may get a pressure spike that may do some bad things to your gun (and you!) There are worse things than breaking down a few rounds and starting over.

 

[Jim Watson]

What is the actual diameter of the expander plug?
It should be noticeably smaller than bullet diameter. Marlin's case neck ID of .354" is too big for adequate bullet pull.

If the expander is not too big, the sizer is. Send it back.

 

[marlin.357]

Jim is right, .354 is too big. Just measured a couple of cases after using a Lee .380 ACP sizing die and .350-.351 ID is closer.

 

[Nhsport]

Yes .380's can be tricky. Have you adjusted the resizeing die so it kisses the shell holder and gives a complete re-size?
I have had similar difficulties with dillion dies on the real short cases of the .380 , it appears the dillion dies have a little more taper at the bottom (to help the die and case to align easier when useing a progressive press?) and they don't resize the case as close to the shellholder as some other dies .
The .380 case is so small that the tollerances are a little tighter. The normal differences in one brand of brass against another brand (both dimensions and hardness) can cause you fits, I always sort my .380 brass into same mfg lots to try to head off some tollerance issues although you are only useing one batch of brass so this isn't your problem.
Have you miked your bullets ? Perhaps a different brand would size out slightly larger and match your cases/resizer die set better. Another way to go is to polish your expander ball down to reduce it's size . You might want to purchase a replacement expander first as you would then have it on hand if you go to far with the polish routine . Another thought is if an expander ball is correctly sized but "rough" in finish it will drag on the case and strech out the brass to a larger size. Either way a light polish seems to be something to try.
Are you getting you brass good and clean ? (tumbler or whatever) A slight bit of crud inside the case neck will have the expander ball draging and streching the brass oversize also.
Different brands of bullets will react differently to what seems the same ammount of taper force. I suppose the inside of your taper crimp die might have a rough patch that is preventing a nice smooth efective crimp ,something else to check out .
Good luck .

 

[kimbernut]

.380 Auto

Might be the die, might be the brass. But that the crimp might hold it is not good enough. Do not take the chance!!! It could hurt you for the rest of your life.
I had the same problem with .380 when I first started reloading but it only occurred with one lot of R-P brass that I had. Tossed that lot of brass and have not had the problem since.

 

[dleong]

Thanks to all who have replied thus far.

I shot my first batch of 380ACP reloads. I had loaded up five test batches:

1. Berry's 100 gr. RNHB, 2.8 gr. Unique, OAL 0.980"
2. Berry's 100 gr. RNHB, 3.0 gr. Unique, OAL 0.980"
3. Berry's 100 gr. RNHB, 3.2 gr. Unique, OAL 0.980"
4. Berry's 100 gr. RNHB, 3.0 gr. Universal, OAL 0.980"
5. Berry's 100 gr. RNHB, 3.2 gr. Universal, OAL 0.980"

It was a total disaster. Despite shooting from a benchrested position, groups and velocities were all over the map. There was a lot of unburned powder spewing out the barrel, which might have screwed up the velocity readings as the powder flakes were making it all the way to and through the chrono. It was obvious that both powders were not burning completely. Perhaps a faster powder would work better--any recommendations?

As for the brass, I just resized them this morning, and actually remembered to measure the inside diameters of the case mouths. I noticed that the Winchester cases resized to about 0.353" while the other brands of cases that were mixed in (R-P, PMC, CBC and S&B) resized to about 0.350". I also recall that most of the problems I had with insufficient neck tension were with the Winchester brass. Do I take this to mean that the Winchester brass is a little on the soft side?

Oh, well. Back to the drawing board...

 

[marlin.357]

I've used 3.2 gr of HP38 or (W231) under Rainier 95 grain round noses with an OAL of 0.975. These are clean, no unburned powder.

For the 100 grain Berry's bullets you could reduce the jacketed load data by 10%. From my Lee manual that would be 3.2 gr - 0.3 gr or a 2.9 gr max of HP38.

As always be careful, and have fun out there.

Just a final thought, you may be OVER crimping. The brass will spring back a little, but the lead won't, resulting in poor bullet retention. Crimp just enough to remove the bell.