How Much Taper (.380 ACP)?

outrider58 · Aug 26, 2020

John from MD said:
Glock mags suck, especially for those of us with arthritic fingers.

Even with the tool, they still suck. I never replace the stub plate except on my HD gun.

lazarus · Aug 27, 2020

John from MD said:
Glock mags suck, especially for those of us with arthritic fingers.

Even those without. If I don't have a maglula handy, my thumb knuckles HURT after loading a couple of mags fully. Usually if I've forgotten my loading tool (I tend to keep a spare in my range bag all the time. Just like I keep a spare 10/22 and 10 round AR-15 mag. Because I tend to forget stuff and I pretty often take a double stack pistol, an AR or a 10/22 to the range).

Anyway, I am only late 30s, no arthritis and in very good shape.

That said, my Cz82 is a little easier to load, but the steel feed lips on it are a lot harder on the fingers.

My Glock 21 mags are easier to load, until the very last round. Then its a beast (and still not "easy")

Anyway, I tend to only load to 10-12 rounds if I forgot my mag loader unless for some reason I NEED to test something with a fully loaded mag.

Which was this most recent time when trying to get it running right with Winchester Ranger-T 147gr +p (needed a slightly stronger spring in the end, running right now). As well as test my 147gr XTP reloads. So I had to load the stinking thing like 6 times to the top. Thumb was sore half the day.

Mark K · Sep 20, 2020

erwos said:
This is your problem. You need stronger mag springs to run +2s. TTI has some.

Well that WASN'T the problem.

I installed the Taran Tactical +2 springs in the three G42 mags that had the +2 extensions, and they were putting way -- WAY -- too much pressure up on the follower and ammo. Almost impossible to load all 8 rounds, even with a Maglula loader. And about impossible to lock a mag with 8 rounds into the gun with the slide forward -- even with a strong smack.

And when starting with a round in the chamber, the gun wouldn't reliably load the next round.

That tells me there was too much pressure up against the slide.

By the way, I had to go all the way up to 3.3 grains of HP-38 (with 100-gn FMJ bullets) to get reliable cycling at the range today. That's right at the max according to Hornady, and .2 grains above max according to Hodgdon... They G42 was pretty snappy, and I was getting some muzzle flash...but it was finally extracting and ejecting well.

U.S.SFC_RET · Sep 25, 2020

Please accept my apology for not monitoring this thread so... I just found out that the caliber 380 is not a tapered round like a 9mm. The 380 is a straight cased cartridge. If you know this then please ignore.

Mark K · Sep 25, 2020

U.S.SFC_RET said:
Please accept my apology for not monitoring this thread so... I just found out that the caliber 380 is not a tapered round like a 9mm. The 380 is a straight cased cartridge. If you know this then please ignore.

Welcome back.

Specs on the .380 ACP are rim diameter of 0.374" (I'm not sure if that's just the rim itself, or the case wall adjacent to the rim), and 0.373" at the mouth.
So yes, pretty-much straight.

But I'm not sure what the difference would be, for purposes of this thread, between a tapered and a straight-walled cartridge case. When I used the term "taper," I didn't mean the case wall itself. I meant the taper crimp holding the bullet in place.

In any case, I think I've got the taper crimp solved. I'm still using the Lee bullet-seating and taper die; and I'm making sure the mouth of the case ends up at just under 0.373", with the COL at just a hair under 0.980". The reloads all pass the plunk test. And I seem to be getting reliable functioning with the Glock 42 at the top load recommended by Hornady (3.3 grains of HP-38 with a 100-gn FMJ bullet).

I'm still playing around with what kind of springs I need for the Strike Industries +2 magazine extensions for the G42. Like I mentioned, I put in TTI +2 springs, and they exerted way too much pressure for reliable chambering. I've switched back to the stock springs (with the +2 mag extensions). We'll see how they work with these cartridge dimensions.

U.S.SFC_RET · Sep 26, 2020

I wouldn’t believe that the cartridge dimensions would have any noticeable effect on cycling.
I just reloaded about 250 or so 380 ACP and didn’t pay any attention to the length of the case just OAL. I adjusted the factory die to remove the ever so slightly bell that was on the case, GTG.

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Mark K · Sep 26, 2020

U.S.SFC_RET said:
I wouldn’t believe that the cartridge dimensions would have any noticeable effect on cycling.
I just reloaded about 250 or so 380 ACP and didn’t pay any attention to the length of the case just OAL. I adjusted the factory die to remove the ever so slightly bell that was on the case, GTG.

I do the same.

Part of the original problem was apparently too large a mouth diameter. I'd previously loaded those cases, didn't fire them, and pulled all the bullets to adjust the powder charge -- that left the mouths belled more than I was used to. I didn't put enough taper on them after that; they didn't feeding right, and it turned out they were failing the plunk test.

There was also not enough powder yet to cycle reliably, but I think I've got that fixed too.

Plus there was apparently an issue with the magazine springs...

U.S.SFC_RET · Sep 26, 2020

I am wondering if your problem could have been corrected if you resized those cases.

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Mark K · Sep 26, 2020

U.S.SFC_RET said:
I am wondering if your problem could have been corrected if you resized those cases.

Resized, how? They were just belled at the mouth, where I'd pulled the bullets. Adjusting the taper crimp die fixed that.

But even with the correct taper, the G42 still wasn't cycling (not enough powder) or feeding (wrong magazine springs) correctly.

U.S.SFC_RET · Sep 27, 2020

Ahh so..
Anywhoo I want to give away 100 rounds of reloaded 380 to some of my extended family members and I will be reloading much more 380 ACP. As far as my experience with reloading this cartridge there is one thing I note. They are fragile when you resize and 5% are lost to crunched case mouths.

John from MD · Sep 27, 2020

U.S.SFC_RET said:
Ahh so..
Anywhoo I want to give away 100 rounds of reloaded 380 to some of my extended family members and I will be reloading much more 380 ACP. As far as my experience with reloading this cartridge there is one thing I note. They are fragile when you resize and 5% are lost to crunched case mouths.

I have to tell you that I have loaded tens of thousands of .380 and the mouths do not have to get crunched. PM me and I will be happy to help you get that remedied.

Mark K · Sep 27, 2020

U.S.SFC_RET said:
I will be reloading much more 380 ACP. As far as my experience with reloading this cartridge there is one thing I note. They are fragile when you resize and 5% are lost to crunched case mouths.

I'd love to hear your experiences. What kind of gun(s) are you reloading for?

When I first started reloading about three years ago, I was having some crushed case mouths too (now that you mention it, mostly with .380, I think -- the straight-walled cases may indeed be more fragile). I don't think I was expanding the case mouths quite enough.

Haven't significantly had that problem recently -- did have it happen once in my last couple runs of 200 rounds each; so that's a quarter-percent loss. I'm expanding the mouths slightly when dropping powder charges.

I'm using 100-gn FMJ Berry's Bullets, which are flat-based. I don't want to expand the case mouths too much so that I'm fatiguing the brass. Just enough so that the bullets barely stay on the case mouths when the ram goes up to the bullet-seating (and taper) die -- I set and press them in with my fingers just enough so they don't fall over sideways, and often "ride" them up with my fingers. Have to be careful I don't pinch my fingers between the case and the die. :rolleyes:

Again, I'm seating and tapering in the same stroke. And I'm not crushing a significant number of cases.

U.S.SFC_RET · Sep 28, 2020

I'd love to hear your experiences. What kind of gun(s) are you reloading for?

Sig P238.

I crunch the case mouths because I am in a hurry with a single stage press. The case mouth taps the side of the die on the way up and thats enough to crunch a 380 casing.

Mark K · Sep 28, 2020

U.S.SFC_RET said:
Sig P238.

I crunch the case mouths because I am in a hurry with a single stage press. The case mouth taps the side of the die on the way up and thats enough to crunch a 380 casing.

What kind of die? Brand? I assume combination bullet-seating and taper-crimping?

I use Lee dies and a Hornady single-stage press... I set up the bullet-seating die like the .380 instructions say: Placing a shell casing (usually one that I've just put the powder into) in the shell holder and raising the ram; screwing down the die until it contacts the case mouth; then I lower the ram and screw the die in about an eighth of a turn further to make sure I have a proper taper-crimp, which is just barely so.

I start with the bullet-seating adjusting screw out so it's not even contacting the bullet, then start to incrementally screw it down while running the ram up and down and checking COL with a micrometer each time.

Once I achieve proper COL, I check whether the case mouth is just a hair under 0.373". I can feel the edge of the case with my finger, but it's tapered into the bullet just enough where it doesn't feel jagged. About half the thickness of the cartridge wall. I put such a minimal taper on, that I don't see any shaving of the bullet by the case mouth.

Once that's all set, I can run the press without damage to the cases. I don't rush, but work up a deliberate rhythm. I just make sure the bullet doesn't slip crooked on top of the case when raising the ram...and I instantly stop raising the ram if I feel anything hanging up, and re-set the case and bullet.

U.S.SFC_RET · Sep 28, 2020

I use the same die as you. My mistakes are not from setting up and adjusting the die. They are from being in a hurry.

Biggfoot44 · Sep 28, 2020

* Straight Wall Cases are More Prone to Crushing Case Mouths * ? Looks over at .32S&W Long , .38spl, .357mag, .41mag, .44spl, .44mag, .45acp, .45Colt , and scratches head .

Mark K · Sep 29, 2020

U.S.SFC_RET said:
I use the same die as you. My mistakes are not from setting up and adjusting the die. They are from being in a hurry.

How do you mean, in a hurry? Are you setting up the die (substantially) like I am?

Does that mean you're, well, ramming the ram up violently? Yeah, that would cause issues.

Immediately when I feel any unusual or sudden resistance, I back off and re-adjust the case in the holder and the bullet on the case.

TGR · Oct 2, 2020

Jeez. This thread gave me a headache reading thru it!

Lots of great advice from folks trying to help. I’m not sure if you solved the original problem, but I’d say you have way too many variables at play. Eliminate some and build a load up for the gun. Just a few points I picked up on the thread.....

I’d start with putting the modified mags aside for now and get an unmodified OEM mag To build the load up with. Eliminate a mag issue.

Most of us have tried to Seat and Crimp in one step at one time or another. The advice you received is dead on.....buy yourself a Lee Factory Crimp die and never look back. This also eliminates a die setup issue. The Seat and Crimp dies are notoriously hard to setup right and keep working correctly.

I’d use a standard COL (eliminate a COL issue) and lock that seating die down. Then setup your crimp on the Factory Crimp die. I also use the push method to verify if It’s enough crimp. Make sure it’s not too much since the 380 headspaces on the mouth.

Make sure the load has enough power to operate the slide. Ladder up a few loads and you’ll find one that works 100%. If you can’t, then you have an issue with the gun.

Once you find a load that functions then start adding the variables such as non-standard mags back in.

Hope it helps and good luck.

Atrox88 · Oct 2, 2020

Mark K said:
In addition, I just micrometered this particular round at the neck -- it's 0.377". Hornady specs show it should be 0.373". And this particular round isn't "plonking" correctly.

My old Sierra reloading data is also showing 0.373

U.S.SFC_RET · Oct 5, 2020

Look guys I crunch approximately 5 percent of my brass when I recap and resize. Its really no big deal to anyone, not even me. It has nothing to do with straight walled or tapered. I think some on this threat are reading into someone that just shouldn't be. I humbly ask for your apology and will succumb to 5 internets. Peace out.

How Much Taper (.380 ACP)?

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