How Much Taper (.380 ACP)?

Mark K · Aug 21, 2020

I haven't found much guidance on how much to taper a casing neck, other than words to the effect of "until it's how you like it."

My wife recently got a Glock 42, and we've been breaking it in. I'm now experimenting with 100-gr FMJ reloads (considering the supply situation these days).

I've been having a bit of a problem with feeding -- rounds occasionally getting caught up at a 45-angle between the magazine and the chamber, requiring the mag to be dropped to clear it. Someone at the gun club suggested that I maybe wasn't tapering the case necks enough after seating the bullets, and the edges were catching up on the feed ramp.

I've always tried to taper as little as possible, just enough to hold the bullet. The guy recommended tapering it in about half the thickness of the brass -- so he could feel the edge on his fingernail, but so it wouldn't catch on the nail. Does that sound right? His reloads were certainly tapered more than mine were.

So what's the correct drill when using a bullet-seating and taper die (Lee in my case)? Get the COL first, then adjust for taper?

outrider58 · Aug 21, 2020

A pic of the fired brass would be nice. May show a rough chamber, which I've had a problem with on some aftermarket barrels. Otherwise, 2-3 thousandths of an inch taper? Am I saying that right?

Also, what type bullet are you shooting?

Mark K · Aug 21, 2020

outrider58 said:
A pic of the fired brass would be nice. May show a rough chamber, which I've had a problem with on some aftermarket barrels. Otherwise, 2-3 thousandths of an inch taper? Am I saying that right?

Also, what type bullet are you shooting?

They're 100-gn FMJ bullets, I think Berry's Bullets.

Here's a photo of one of the unfired (re-)loaded rounds, one of the batch that was causing me problems:

So the background on this particular batch of 100 rounds was, I originally had them loaded way too weak -- 2.9 grains of HP-38, and my wife's new Glock 42 absolutely hated them. Constant FTFs, with spent casings just dribbling out instead of ejecting like they should.

So with the scarcity of components these days, I took the 100 rounds I had remaining, pulled the bullets (that's why you see that collet mark on the bullet), and re-loaded them with 3.1 grains of HP-38.

I noticed the case necks were way loose after pulling the bullets. After they were re-loaded, the rounds wouldn't "plonk" properly into the G42 barrel, and wouldn't drop free. So I tried tapering all of them down to what I thought was spec (I micrometered a sample); they then seemed to be "plonking" properly.

You can see how little taper there is in the image. 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.

So it may be a related combination of too little taper, and too much diameter.

If you agree, then what's the procedure when pressing in a bullet? In this case with a Lee bullet seating die?

U.S.SFC_RET · Aug 22, 2020

Set the die for bullet depth.

Back off the bullet depth adjuster a couple of turns.

Now that you have a bullet set for proper depth run the ram with the seated bullet all the way up and start with 1/16th turns on the bullet seating die. You are tapering when you begin to notice an ever so bit of resistance. Check your bullet using the pushing method against the reloading table. When you are happy with the amount of taper reset your seating depth with the bullet ran all the way up.

John from MD · Aug 22, 2020

If the round is getting caught at a 45 degree angle, your problem is not with OAl. OAL problems on blowbacks usually will feed fine but they won't chamber all the way. You have a feeding problem from the magazine to the chamber. In this case, I believe you are loading your ammo too light and not getting full slide travel all the time. Go up to 3.3 or 3.4, it won't hurt anything.

outrider58 · Aug 22, 2020

John from MD said:
If the round is getting caught at a 45 degree angle, your problem is not with OAl. OAL problems on blowbacks usually will feed fine but they won't chamber all the way. You have a feeding problem from the magazine to the chamber. In this case, I believe you are loading your ammo too light and not getting full slide travel all the time. Go up to 3.3 or 3.4, it won't hurt anything.

I'd still like to see a couple pieces of fired brass, but yeah, maybe just too light of a load along with not enough taper. A tighter taper will solve two problems. Consistent feeding and consistent round power(in turn will aid in consistent extraction).

OP, if you like the lighter power/recoil of the round and load, you can always back off the recoil spring weight. I have run into similar situations when developing loads for my 9mm P80s. I would end up with too light a load. Instead of pulling them all(I admit, I prefer a heavy taper), I keep a bit lighter spring on hand to swap out and shoot up the lighter ammo. My arthritic wrists thank me.

Mark K · Aug 22, 2020

U.S.SFC_RET said:
Check your bullet using the pushing method against the reloading table. When you are happy with the amount of taper

So what's the "pushing method?" I assume pushing the seated bullet down against the bench, and seeing if it moves farther into the casing? How much pressure? In other words, how will I know if I'm happy with the taper?

Thanks for the procedure, by the way. I'll try that.

John from MD said:
In this case, I believe you are loading your ammo too light and not getting full slide travel all the time. Go up to 3.3 or 3.4, it won't hurt anything.

Well, that occurred to me too. The previous 2.9-gr loads were definitely too anemic. My concern is that Lee and Hodgdon load data agree that 3.1 grains of HP-38 is the absolute max load for a 100-gr bullet. That's what these last batches were loaded to.

Hornady is the outlier, allowing 3.3 grains -- which concerns me. I'm really hesitant to over-load, since I recently destroyed my Bersa 380CC using hot commercial ammo...

outrider58 said:
I'd still like to see a couple pieces of fired brass

I actually did sweep up my brass and bring it home, as always. I don't know which is from the batch that I pulled and re-re-loaded, and which had been reloaded to 3.1 grains originally. What would you be looking for -- how should I take photos?

outrider58 said:
but yeah, maybe just too light of a load along with not enough taper. A tighter taper will solve two problems. Consistent feeding and consistent round power(in turn will aid in consistent extraction).

Funny you should mention extraction. Even with the batch that hadn't been pulled, I was getting a few extraction/ejection problems -- I had a couple stove-pipes, and a few times the casing just remained in the chamber...not stuck, just didn't extract and/or eject...

I'm thinking taper right now, since I'm right up at the upper recommended load (according to most sources). I'll play around with adjusting the taper today or tomorrow...

outrider58 · Aug 22, 2020

Mark K said:
I actually did sweep up my brass and bring it home, as always. I don't know which is from the batch that I pulled and re-re-loaded, and which had been reloaded to 3.1 grains originally. What would you be looking for -- how should I take photos?

If you are looking for a rough chamber, you would be looking for 'frosted' cases. These are from my g20. The one in the middle is after polishing the chamber. The two on the outside are frosted. The chamber was so rough, I had to hand feed each round into the chamber. It could probably stand some more polishing, but for now, the gun runs and feeds fine.

Mark K · Aug 22, 2020

U.S.SFC_RET said:
When you are happy with the amount of taper reset your seating depth with the bullet ran all the way up.

OK, I've been thinking about this. It all makes sense, except this part.

How do I re-set the bullet seating depth after adjusting the taper? Since I'll be screwing in the bullet seating part of the die, I don't think I'll be able to feel when it just touches the tip of the bullet. Seems like I'd risk pushing the bullet too far into the casing.

Or -- with the proper amount of crimp -- would the bullet not push in, and I'd feel resistance?

John from MD · Aug 22, 2020

Are you seating and crimping with the same die?

Mark K · Aug 22, 2020

outrider58 said:
I'd still like to see a couple pieces of fired brass

Here's more than a couple -- a random sampling from the 150 total rounds I fired. Of the 150, 100 were re-re-loaded (after pulling the bullets from the anemic loads), and 50 were not previously pulled. All 150-GR FMJ, with 3.1 grains of HP-38. Hope you can glean something. (Both images are of the same bunch, just turned around so you can see the bases and the mouths.)

Mark K · Aug 22, 2020

John from MD said:
Are you seating and crimping with the same die?

Yes. Lee bullet seating die.

The die set only came with three dies -- no separate crimp or taper die.

John from MD · Aug 22, 2020

Mark K said:
Yes. Lee bullet seating die.

The die set only came with three dies -- no separate crimp or taper die.

Ok, that is the number one thing you need to change. You need to buy a Lee factory crimp die and crimp separately. That will allow you to adjust the seating die to just seat the bullet and straighten out the bell in the case mouth. Then, the Lee FCD allows you to taper crimp the mouth to the dimension that you choose.

It is one extra step but I will make a big difference in the quality of your reloads as the FCD is pretty tolerant about case length where a seating die isn't.

outrider58 · Aug 22, 2020

Mark K said:
Here's more than a couple -- a random sampling from the 150 total rounds I fired. Of the 150, 100 were re-re-loaded (after pulling the bullets from the anemic loads), and 50 were not previously pulled. All 150-GR FMJ, with 3.1 grains of HP-38. Hope you can glean something. (Both images are of the same bunch, just turned around so you can see the bases and the mouths.)

It's kinda hard to tell at those magnifications. They look a little rough, but that could be due to lighting and magnification. Always good to through a factory, improved or unfired piece in there for comparison. Let's get your crimp working first, then maybe revisit the chamber later, if need be.

outrider58 · Aug 22, 2020

John from MD said:
Ok, that is the number one thing you need to change. You need to buy a Lee factory crimp die and crimp separately. That will allow you to adjust the seating die to just seat the bullet and straighten out the bell in the case mouth. Then, the Lee FCD allows you to taper crimp the mouth to the dimension that you choose.

It is one extra step but I will make a big difference in the quality of your reloads as the FCD is pretty tolerant about case length where a seating die isn't.

Mark K · Aug 22, 2020

outrider58 said:
maybe revisit the chamber later, if need be.

You mentioned previously that you'd had rough chambers with aftermarket barrels. Well, this is a brand-new stock barrel on the Glock 42...

Mark K · Aug 22, 2020

John from MD said:
Ok, that is the number one thing you need to change. You need to buy a Lee factory crimp die and crimp separately.

outrider58 said:

OK, you two guys are now saying I need a separate crimp die. While U.S.SFC_RET indicated in Post #4 that I need to -- or can -- continue with the bullet seating and taper die.

The instructions for the Lee dies say that a Lee "Factory Crimp Die" is optional. But it only talks about it crimping; while I'm just trying for a slight taper as far as I know. Is a Factory Crimp Die (and an extra step) really necessary? (I've only got a single-stage press.)

Or can I play around with just the combination die for now, as U.S.SFC_RET suggested?

Mark K · Aug 22, 2020

outrider58 said:
They look a little rough

I clean the casings ultrasonically, but don't polish them. That may be why they look that way...

Mark K · Aug 22, 2020

OK, let me review for myself the function of each die...

Here's an image I found a few years ago of the cross-sections of Lee dies:

First, the decapper and sizing die removes the primer (of course), and sizes the outside of the case. Yes? Does it give the slight taper along the case length, with the mouth of the case supposed to be 0.001" narrower than the base?

That's important because, like I said, I found that the case mouths were really belled after I pulled all those bullets from the anemic cartridges. I didn't run the casings through the sizing die again, but just used the bullet seating and taper die thinking that would tighten down the mouths. I don't think I fixed the belling properly, in addition to having too little taper...

Second, the powder/expander die bells the case mouth slightly, so the bullet stays put during the next step before the ram is raised.

Third, the seating die is supposed to simultaneously seat the bullet, and apply a taper.

Finally, and optionally, the factory crimp die applies a crimp if desired.

outrider58 · Aug 22, 2020

Mark K said:
OK, let me review for myself the function of each die...

Here's an image I found a few years ago of the cross-sections of Lee dies:

First, the decapper and sizing die removes the primer (of course), and sizes the outside of the case. Yes? Does it give the slight taper along the case length, with the mouth of the case supposed to be 0.001" narrower than the base?

That's important because, like I said, I found that the case mouths were really belled after I pulled all those bullets from the anemic cartridges. I didn't run the casings through the sizing die again, but just used the bullet seating and taper die thinking that would tighten down the mouths. I don't think I fixed the belling properly, in addition to having too little taper...

Second, the powder/expander die bells the case mouth slightly, so the bullet stays put during the next step before the ram is raised.

Third, the seating die is supposed to simultaneously seat the bullet, and apply a taper.

Finally, and optionally, the factory crimp die applies a crimp if desired.

I'm sorry. It would help immensely to know what you are reloading on, as far as what press you are using.
The first rule of reloading any cartridge that has to be belled or flared is, never seat and crimp a round in the same stage. I know some die manufacturers say you can, but don't. Seat all your bullets, then crimp(or remove the flare or bell) separately in a separate stage.
You can use the same die to seat and crimp, but it should be done separately. That way, you don't have to readjust your seating die every time you go back to load more of the same round.

How Much Taper (.380 ACP)?

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