Glad I found this thread.  It happens that I have began experimenting with loads in .380 too.  
I don't have data in front of me at the moment because I'm at work. Loads that I have worked up to test include ,
90 gr. XTP's loaded with Titegroup, 88gr Remington JHP's also loaded with Titegroup and some 115gr Rainier plated HP's loaded with Red Dot. These will all be fired from a Glock 42.

So far the only thing I have fired has been a few of the Remington 88gr loads. The weather has been too wet to get very serious about testing. I haven't set up the chrono and got any decent data yet, but the few different charge weights that I fired between rain showers off the deck indicated that about 3.1grs of Titegroup was the sweet spot for the 88's.

I was resizing some of my .380 brass this morning when I happened upon a couple of the Federal cases I was able to properly seat a bullet and fire. I noticed that those which slightly buckled (yet plunk tested and fired) did not "iron out" the buckle, or better put, form to the chamber. Then I grabbed my calipers and started measuring the depth of the step found in the Federal cases.  The step measures a fairly consistent .1875" deep from the case mouth.

None of my other mixed brass has this step nor does my new Star Line brass.

Since this stepped brass is such a pain to bell or even seat a bullet I think any stepped brass will go into the recycle bin.

Just ordered a box of 90g XTPs to experiment with.  

Plan on sticking with my favorite 4.2g of Power Pistol that I use for the 100g Berrys to start.

That should scoot them right along.    I'm showing a max load of 4.8g of Power Pistol for the 90g XTP.  I don't think I want them anywhere near that hot.

I'm planning to start reloading .380 ACP, and I once I went searching was pleased to see this thread had been toggled to stay out of the archive. Thought I'd bump it up to see if anyone has additional insight since the last post.

I have 1,000 95 gr .355 FMJ bullets on order from Rocky Mountain Reloading that I'll use as projectiles.

Plan to use Power Pistol for my first charge ladder.

I have about 2,000 pieces of range pickup brass, about 500 of which is my once fired and the rest I purchased from EE sales.  I know at least one poster earlier in this thread mentioned sorting by headstamp due to small case capacity of .380, and I think I'll take that route.

I'll update with my results.

Thanks!  Good information in that thread as well.

AR's thread is great, a step-by step account of developing a load, testing it, then producing a butt-load of that load.

I chose AA#5 for my .380 loading because it's bulkier than many other powders that "work" in that caliber.  One issue with loading any caliber is the ratio of powder load to available space in the case.  With .380, there are a whole lot of powders that "work," but a lot of them have pretty small max charge weights.  I was concerned that I wouldn't be able to spot an incomplete or double charge, so I started studying the loading manuals, particularly from powder makers.

I identified a number of powders that worked with 85-115 grain bullets in .380, and then looked at their densities.  Western/Ramshot/Accurate powders have densities listed on each powder's product page in several types of units, so that made it easy.

Power Pistol has a higher VMD than AA#5; PP is less dense than #5, but not by a whole lot.  By my criteria (including density), it should be a good choice for .380.

I set up my press for .380 and tumbled some brass clean today.

I separated my clean brass by headstamp, and started working with thevWinchrster casings as this headstamp made up about 1/3 of my casings.

I’m having real problems with the decapping rod during resizing.  I’m using Lee dies, and about half the time the die fails to push out the spent primer and instead moves up from the die collet to preserve the decapping rod.

My decapping rod is okay, but each time I have to disassemble the die to restore the decapping rod position.

Something is clearly wrong.  I gave up on the Winchester casings after attempt #11, where I experienced the fifth failure to decap.

I reset my die and tried with another headstamp, decapping and resizing about 25 casings in a row with zero issues.

Any ideas what might be causing this issue in the Winchester casings?

Tightening the collet a small additional amount seemed to do the trick.  I successfully resized and decapped 10 or so Win cases after trying this, including the pile of Win brass that was problematic.

Maybe  Win .380 cases I’m working with must have tighter fitting primers than other cases?  Seems to be working now so I can proceed.

Thanks!

I use W231 for my .380 loads.

I've run from 2.6 gr. to 3.2 gr. with 100 gr. plated Berry's and Xtreme RN's.  COAL is about .980 or slightly less.

In general, I tend to run lighter loads because I'm not using them for PD, just plinking.

I'm also using my ppk and Colt 1908 for my shooting.  I'm not interested in higher power loads in these two older pieces.

My average velocity ranges are:

2.6 gr = 658 fps
2.8 gr = 758 fps
3.2 gr = 826 fps

I've centered on the 2.8 gr load because of good accuracy and relatively light load character.

My best target/practice load for the .380Auto in the G42 is;

Bullet: Remington 95gr FMJ RN
Case: Rem., Win., Fiocchi, Fed., Starline, COL .960"
Powder: Bullseye, 3.4grs.
Primer: CCI 500
Velocity: 935fps (chronoed)

ETA:
My self defense load (that is in my G42 right now) is:

Bullet: Hornady 90gr HP XTP
Case: same as above, but I usually use new or only once or twice fired cases, COL .965"
Powder: Power Pistol, 4.7grs.
Primer: CCI 500
Velocity: 1,000fps (chronoed)

I definitely plan to try W231.  I have a lot of W231 in my stockpile, so a lighter shooting W231 practice load that still reliably cycles my LCP would be a good thing.

I just started loading .380 so I’ll add what I decided on. I ended up using AA#2 because I have a lot of it and I knew it would work. My FPS was faster than what Accurate has in their online pdf manual for the same bullet I used.  Interesting because I used a P238 which only has a 2.7” barrel.

Bullet: 100gr Berry’s RNHB
Powder: 2.8 gr AA#2
Primer: Federal
OAL: 0.96
FPS : around 830

Cases were mixed.

Anyone have any experience with the headstamp “G.F.L. .380 Auto” brass?

I tried to seat a 95gr FMJ RN bullet to .980” COL and it’s like I hit a hard stop when the bullet is around .990” COL.

The press will not seat the bullet deeper in this brass.

Brass is fully resized, and the same die setup works fine on other headstamp brass.

This is strange.

G F L is Fiocchi, and it should be good stuff.  A "hard stop" seating the bullet sounds like there's some sort of shelf in the case, but I haven't seen any Fiocchi brass like that.

Maxx Tech makes 9mm brass with a step in the case.  It looks like this:

(Image stolen from TaurusArmed forums.)

But I'd bet you would have noticed a step in your 380 cases while processing them, so unless you're stopping on a "compressed load" of powder, I'm out of ideas.

Disregard- 2 year old thread.... you probably got it figured out by now it appears!

I need to load some .380 for my Beretta soon...

I solved it by separating out all this headstamp and setting it aside

It’s still off in my brass storage somewhere.   About to start another batch with summer coming up, so I’d be curious if you had some insight.