Finding a sweet spot between shaving bullets and dropping them into the case? 9mm

[BHuij]

I have been casting and loading 9mm bullets for my M&P 9 for years now. After the standard initial goose chase of "why am I still getting leading", I figured out what worked:

1. My OEM barrel slugged at .357" in the grooves using a micrometer. I sized bullets to .3585" after powder coating.
2. The stock expander plug in my Lee powder-through expander die wasn't opening the case mouth enough to avoid swaging the bullet upon seating. I swapped it out for a .38 S&W expander plug as recommended in many forum posts on the subject, and the cases no longer swaged my bullets. I also made sure my seating die was set up such that it didn't do any crimping, ONLY seating.
3. The factory crimp die has the carbide ring that squishes everything back down to SAAMI spec, once again resulting in undersize bullets that were leading my bore. After unsuccessfully trying for a while to knock out the carbide ring so I could still use the crimp die, I finally gave up. I found a sweet spot with my expander die where I could get bullets seated without difficulty, but once they were seated, they were firm and I couldn't push them in any further with finger pressure. So that's how I loaded my last ~15,000 rounds or so. No issues.

Here's the deal. I just put in an Apex match grade barrel in the gun. After noticing that my normal handloads using .3585" bullets were having a hard time chambering, I slugged the bore and found that the groove diameter is just a hair larger than .355". So I sized several bullets down to .356" and loaded them. I had to adjust my expander die, as it was too aggressive for the slightly smaller bullets, and tried to find a sweet spot where I could seat the bullets without trouble, but wasn't worried about having not enough neck tension.

I'm not sure this sweet spot exists. About 60% of the bullets were shaving a little bit upon seating. About 20% felt very little tension as they were being seated; much less than I'm used to (although they also did not budge when I pushed on them with my thumbs after seating). The remaining 20% seemed normal.

Everything chambered normally and I had zero problems at the range that night. The new barrel is absolutely grouping significantly better than the OEM one. All the charges I tested shot basically the same, so I'm going to stick with the 4gr of W231 I've been using for years.

Is there some solution here that I could implement to get back to a place where I'm not simultaneously too tight and too loose on the case mouth? Or should I just bell the mouth a little more and then find a crimp die solution that doesn't swage my bullets back down?

Edit: Lee taper crimp die without the carbide ring is on sale right now. This is a small cost to pay to solve my problem, will this die allow me to get good neck tension from a belled case mouth without swaging my bullet?

Lee Taper Crimp Die 9mm Luger

The Lee Taper Crimp Die is hardened steel designed to overcome crimp problems caused by poor die design. These dies offer little or no advantage when...

www.midwayusa.com

 

[Petrol & Powder]

I'm going to address a couple of your points and hope I get it right.

Frist - 9mm barrels are all over the map in terms of size and I think you have found yet another example of that old truth.
Second - I recommend an expander with something similar to a Lyman Type M expander with the "step" instead of a "bell" type flare. I have found NOTHING better when dealing with cast bullets. If you are using .355" bullets, then that is the diamter you want for the primary portion of the expander. The brass will spring back and end up being slightly less than .355" and that will provide any needed neck tension. The larger portion of the expander (The "Step") that opens the very end of the case mouth, should be just big enough to expand the case to accept the bullet without shaving. I find that step needs to be a little more than the final bullet diameter because of that brass "spring back". So probably something around .356"? You'll have to try to see where that diameter needs to be.
3. A separate taper crimp is is absolutely the way to go. Once you get the expander operation set correctly & the seating operation set correctly, a taper crimp can be adjusted to achieve whatever amount of crimp you desire.

Personally, I perfer the Redding taper crimp dies for their internal profile and high quality but that's just a preference.

And last - Your brass doesn't need to be all the same make but it damn sure needs to be roughly the same in terms of wall thickness and length. Which sometimes means ....mostly the same make.
I've had very good luck with mixed manufacturers of 9mm brass BUT there are a few outliers, so if your brass is mixed, pay attention to the cases that give you trouble. You may need to cull those.

The increased accuracy seen with your new barrel ls likely a result of the tighter tolerences on the barrel's EXTERIOR than on the internal tolerences. It is the improved fit of the barrel to the slide where those gains are made. So while the new barrel has a bore diamter that is closer to what 9mm luger should be (.355") the real benefit comes from the improved barrel to slide fit.

 

[BHuij]

What you're saying makes sense. Since I'm $10 away from a possible solution here, I'm going to try with my existing expander die first. If I can get good seating without sacrificing too much neck tension, then taper crimp back down for consistency and easy chambering, that's probably ideal.

If I can't get it to work with that setup, I'll check out a stepped expander. Does the M die have a plug you can put in for 9mm cases with cast bullets? Or better yet, is there one available that works with the Lee Universal expander? I already have that die.

The increased accuracy with the new barrel is a result of lots of things, but I think the primary improvement is that Apex fixed the barrel geometry that caused early unlocking in M&P OEM barrels. Now the barrel stays absolutely put while the bullet is still inside of it and only unlocks after the projectile has exited the muzzle. Pair that with the better fitment of barrel to slide and it makes perfect sense why it immediately closed down my groups.

 

[Petrol & Powder]

Your existing expander (for 38 S&W) is considerably larger than needed for your new smaller bullet and you will overwork the brass. That will shorten the case life. If you have a smaller expander that is closer to .355”, I would go with that.

The Lyman Type M expander does have a removable plug, but I don’t know if it is compatible with other manufacturers’ dies.

 

[BHuij]

Doing a bunch more reading, it seems like there are several options for getting the right amount of case mouth expansion, most of which would require a separate crimp step afterwards (which is fine). I went ahead and grabbed that taper crimp die. I will experiment with my existing .38S&W expander plug. It seems like it's probably just a bit oversized, which could be fixed easily with sandpaper.

I'm hoping to stay away from the M-die solution, because if I can get my powder through expander die to work with a properly sized plug, I'll be in a better position to finally step up to a turret press setup.

 

[fiver]

you wouldn't be the first one to apply the crocus cloth and steel wool diameter repair kit.

 

[BHuij]

So I'll need to do some testing, take some measurements, seat/pull some bullets, etc. But what would be the ideal neck tension for a standard 120gr, 125 PF coated lead bullet?

 

[Petrol & Powder]

You may be over thinking this a bit.

Expand the case deep enough to match the amount that the bullet is seated in the casing and expand the case to the same diameter as the bullet that you are seating. When the expander is removed, the brass will spring back a little and provide the needed neck tension. After seating the bullet, apply a taper crimp to hold the bullet and remove any flare from the expanding procedure.

That taper crimp only needs to be enough to hold the bullet in place during the recoil of other rounds.

The taper crimp will only affect the area near the case mouth and doesn't need to be excessive. Some magnum revolver cartridges with slow burning powders benefit from a heavy crimp but most semi-auto pistol cartridges just need enough crimp to reliably hold the bullet in place.

 

[CZ93X62]

Castings in 9mm--greased or coated--can be a PITA. I agree with the ideas above--expander spud primary diameter at target bullet diameter, and the M-die flaring collars tend to be .0035"-.004" larger than the spec diameter.

The Lyman Multi-Charge Die kit includes power-through-expander spuds for both 38/357 loading (#38P) and 9mm/38 Super loading (#38AP). Mic their diameters and do whatever steel wool/crocus cloth adjustments are indicated. I have used the this Lyman system on my Ponsness-Warren P-200 for 15 years, with 9mm barrels that spec .357"--all of them, miraculously. I finish with a taper crimp die LIGHTLY. Mongo has no place in the taper crimping of autopistol cartridges loaded with cast bullets.

 

[STIHL]

Well I haven’t ran into this yet, I use a factory crimp on 45Auto all the time and never have issues, but all mine are sized .452, with that being said I’m with fiver I’d open that baby up to your desired needs. I love the factory crimp dies, and for the price you can buy one and modify it and not break the bank if you end up needing 2-3 of them for 9 mil.

 

[Petrol & Powder]

I've never seen a need to modify a taper crimp die. You simply screw it in or out of the press to achieve the desired amount of crimp. And I think Al and I are in agreement, with cartridges used in a semi-auto pistol, you don’t want or need a lot of taper crimp.

I could see the need to modify an expander but at some point, it becomes easier to just buy one of the needed dimensions or, if you have a lathe; make one.

When using cast bullets, the Lyman “M” style expander works very well. It doesn’t need to be an actual Lyman expander, just that form of expander.

The Lyman “M” type expander doesn’t open the case mouth like a trumpet bell but instead opens the case mouth parallel to the case just enough to accept the bullet. After the bullet is seated, a taper crimp die removes any slight flare left over from the expander but shouldn’t significantly squeeze the bullet down. Neck tension and a LITTLE bit of taper crimp is all that is needed to keep the bullet in place. And remember, rimless pistol cartridges headspace on the case mouth, so if you get too crazy with the taper crimp, you’ll start to interfere with that function as well.

 

[STIHL]

petrol that all makes really good sense and I understand, may be easier than the way ive been doing it.
I’ll have to look at the M expander.

I may be bad off on this, but I thought in the FCD that ring in the bottom of the dies was basically a body die that pushed the bell back in to SAMMI spec and then you hit the taper “crimp” portion of the die. If you open that ring up, would it not accomplish the same thing?

 

[Petrol & Powder]

"....I may be bad off on this, but I thought in the FCD that ring in the bottom of the dies was basically a body die that pushed the bell back in to SAMMI spec and then you hit the taper “crimp” portion of the die. If you open that ring up, would it not accomplish the same thing?"


A taper crimp die is exactly what it claims to be - a taper. And it's only a taper at the very top of the die near the case mouth. When a casing is pushed into a taper crimp die the upper section (and only the upper section) of the casing is pushed inward on the bullet. The farther you push the casing into that taper, the more crimp it applies until you reach the point that the casing can't be pushed any deeper into the die. You want less crimp? - back the die out of the press. You want more crimp (within the ability of the die) you screw the die deeper into the press. It ain’t rocket surgery.

A roll crimp die does the same thing except the profile of the crimping section is different. A roll crimp die curls the case mouth inward with a steep radius. (hopefully into a corresponding crimp groove in the bullet).

The Lee Factory Crimp Die adds a separate collet to the die. That collet squeezes the casing inward. While it does focus the crimping force perpendicular to the outer case wall and therefore pushes the casing directly into the bullet, it accomplishes the same thing as standard crimping dies.

Some people swear by the Lee FCD and some people swear at it. I’m in the latter category. I have NEVER seen the advantage of a Lee FCD and think it is nothing more than an overrated gimmick. That’s my personal opinion, you’re welcome to disagree.

I use a roll crimp for revolver cartridges and a taper crimp for pistol cartridges and most bottle neck rifle cartridges.

This stuff gets unnecessarily complicated. The function of the crimp is to remove any remaining flare at the case mouth and to provide enough tension to adequately retain the bullet in the casing under recoil. In some situations, with slow burning magnum powders, a heavy crimp is needed to hold the bullet in place as pressure builds during the early ignition process. For the most part, the job of the crimp is to just hold the bullet in place until the cartridge is fired.

 

[fiver]

I have NEVER seen the advantage of a Lee FCD

in Richard LEE's book he goes into great detail explaining the invention of the FCD.
it goes something like this.[I'm paraphrasing just a little]
A. a we have several barrels full of expensive carbide rings that are too big for case sizing.
B. scrap price is far less than cost.
C. hey!!! we can make them a little bigger, size already sized cases and charge full price for our scrap metal.
D. fire the dude that made them too big in the first place.

 

[462]

Yep, that's exactly how it happened. Except the guy didn't get fired -- he got promoted to the quality control department and works alongside Shirley.

 

[STIHL]

Ok I may have misunderstood terminology here. I fall in the first category with Lee factory crimp dies. I like them, they have served me well with what I have loaded thus far and that’s what I thought This post was referring to was the Lee FCD, now I realize we are talking a taper crimp die which is completely different. I’m going to shut up now and go back over here and sit down!!! What I get for thinking after a long day.

 

[fiver]

that was the guy that come up with the AHA! moment,,,,, not the cockeyed machine operator.
the machine guy somehow got over to Remington and hired to hand chamber their rifle barrels,,, eventually being promoted to putting the barrels on the new marlin line of lever guns.


here he is with his first paycheck.

 

[462]

So, then, Shirley is the entire quality control department? Well, that explains that and most everything else.

 

[RBHarter]

A missed foot note . There are 2 different FCD dies . One , the post sizer we love to hate with the sliding crimp collar inside , an the collet crimp die .
In my extremely limited experience the collet/finger die doesn't size anything and is only vaguely shaped like the intended cartridge . It's only case contact except in unusually large out of spec cases is the crimp point at the mouth of the case . I've only used said collet dies for 30-30 and 45-70 and the 30-30 trial was with a 308 die . In 45-70 it allowed me better control of crimp with what I was doing at the time which is off the table altogether now . Not much call for it in 30-30 bolts and singles either ......

 

[Petrol & Powder]

Yes, there are two different styles of Lee crimp dies commonly known as FCD.

They are BOTH equally suited as fishing net weights, although there are generally less expensive options available.