Rifle case mouth flaring?

D

dyl

New member
Hi all,

But my question is this: I held up a projectile to the case mouth after it was "expanded" by the sizer/decapping die. And if this is considered expanded, it ain't by much. I'm pretty sure it would scrape the powder coating off. Is it normal for rifle brass in 2 die combos to not have a flare like pistol brass?

Context below:
I've just started loading rifle. I have a 300 Blackout 2 Die set, and after I've resized / converted some brass from .223, I held up a bullet (hard cast powder coated 245 grain from ACME) to the case mouth and it's not very flared. Projectile diameter 0.310 So I thought: I need to lower the expander-Decapping rod further down. No difference, so I lowered and lowered it until I believe it impacted the brass leaving imprints of the shell holder on the base of the casing. Of course, this bent the threaded portion of the Expander-Decapping rod. I contacted RCBS about the best way to straighten it, but I can order a replacement cheap from the... Tropical River company.
 
Try and get someone local who knows how to reload to help you . You do not understand how rifle dies work . An explanation in person would help .
 
Rifle dies typically do not get flared for jacketed bullets, a little chamfer is usually all that is needed so rifle dies typically don't come with a flarer. But if you load lead (PCed or lubed) you'll need something like a Lyman M die or a Lee Universal Expander to flare the case a bit.
 
You are correct that rifle dies do no flare the case mouth. During sizing the expander plug is pulled back through the case neck which has been squeezed down by the neck portion of the sizing die and normally sizes the neck to .002"-.003" smaller ID than the bullet. When loading cast bullets I normally flare the case necks to prevent shaving lead (or PC). Lee makes a Universal Expanding die...
 
Thank you, I've read that the expanding ball works upon withdrawing the case from the die and it refers to expanding the inner diameter (rather than the case mouth), I laid eyes on the top of the expanding ball which seems to get wider and thought: why can't they make a funnel at the top to flare/bell the case mouth too? The expander ball could still drop down deep enough and size upon withdrawing...

Do you know of any expander ball or any small base resizing die that combines resizing and flaring the case mouth at the same time?
 
2 die rifle sets are designed from the get go to reload jacketed bullets . Jacketed bullets are smaller in diameter than plain lead , coated lead or plated lead .
When you get into reloading lead , plain lubed , coated or plated you will need an additional die or two to make the case necks larger so they will accept the larger bullets . First is the Lyman M die is for expanding the case neck wide enough for cast bullet and it provides a way to seat the softer bullet without shaving lead from the bullet side .

Now some dies are manufactured to load lead bullets , they are usually 3 die sets and may be marked " Cowboy Action " dies ...that sport only allows the use of lead bullets .

It's not simply a larger expander ball , you must have a flaring tool like the Lyman M die to get the neck flared correctly for bullet seating .
Lee makes a Universal Flaring Tool which works fairly well but NOE makes some little expander plugs that work like the Lyman M die and the two (Lee Universal Flaring + NOE neck expander plug ) do the best job and cost less than Lyman M dies if you have many different cast bullet rounds you load for .

Loading cast is a bit trickier than jacketed but by just doing a couple extra steps with the right tool(s) it's not hard and I really enjoy shooting bullets I've cast myself .
Gary
 
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Rifle case mouth flaring isn't done with bottle necked cases like the .300 BO. Jacketed bullets or cast doesn't matter. That's why you chamfer the inside of the case mouth.
Lee calls theirs a Chamfering Tool. It's kind of slow, but it's also less than $5. Been using one for eons myself. And it's only done with new brass and after you trim.
https://leeprecision.com/chamfer-tool.html
Straight walled rifle cases get flared just like a handgun case.
 
I'll disagree about it not mattering to cast bullets. They shave too easily. You want a Lyman M die or a universal expander to prevent that, as it deteriorates accuracy and increases metal fouling in the throat.

My recommendation is to get yourself a Lyman M die. This is for two reasons. I have experimented in the past with burnishing and flaring rifle case mouths and found it beneficial. I got onto the idea initially because I found little rings of scraped copper around the necks of some commercially loaded ammunition and realized that while a jacket is tougher than lead, it is not steel. It can still be scraped. And if you have just chamfered the case neck, the edge of the chamfer is a sharp enough corner to scrape well.

The Lyman M-die is simple but very helpful. It has two neck expanding features. One is a small step that widens the case mouth for a short distance just enough for the bullet to slip into the step. The second, if you force the case into it deeper, produces a conventional conical flare at the top end of the step. For jacketed bullets, you don't need that second stage conical flare. All you need is the step, so you set the die depth to produce only that. The step not only stops scraping, but it also lets you set the bullet into the neck so it remains upright. Because of that, you don't need to keep your fingers on it as it enters the seating die. It will stay straight up. Because it is straight, the bullet doesn't contact the seating die ram (stem tip) at a funny angle so it doesn't get into a race to try to straighten up before seating begins to push it into the neck. As a result, it seats significantly straighter into the case, reducing runout, in my tests, by a factor of about four. That has a measurable effect on accuracy with most boattail bullets, especially those with secant ogives. YMMV, but I consider the M-die a basic accuracy reloading tool at this point.

When you use one of these dies, you typically set the seater up so it's crimp shoulder just kisses the case mouth and irons out the step, but I have not found that essential. If your chamber is wide enough to accommodate the step without ironing it out, that actually helps center the bullet with the bore, and that helps accuracy as well.
 
If your loading ANY cast bullet in ANY caliber you want to flare the mouth and the easiest and cheapest way is the Lee universal tool.
 
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. Is it normal for rifle brass in 2 die combos to not have a flare like pistol brass?
Click to expand...

Yes, this is normal.

Two die sets are for loading bottlenecked cases, and most people load bottlenecked cases with jacketed bullets. For those who do load lead, they get and use a flaring tool (such as the Lyman die).

Understand the slight, but significant difference between "expand" and "flare" as used in reloading. Sizing dies (all of them) squeeze the case slightly smaller than "new" on the outside, and this reduces the inside of the neck to a diameter that is too small to correctly take the bullet. The inside of the neck must then be "expanded" back UP to correct size.

This is what the expander ball does when you pull the case out of the sizing die. Straight wall cases require a separate expander die, to do this.

Normally, expander dies can also "flare" the case mouth (one adjusts to get the amount desired) creating the little "step" Uncle Nick talked about. This is done so you can easily start bullets in the case mouth, straight, and you always WANT to do that with lead bullets. ("Coated" bullets are lead bullets)

It's also a benefit loading jacketed bullets too, but its not the virtual necessity with jacketed that it is with lead.

The "flare" must be removed (case straightened) and normally the seating die does that.

My personal preference is Lyman. The "M" die is the expander/flare die and its the middle die of the 3 die set. The die body is "universal" and you can get expanding stems for every desired caliber.

BE AWARE that you can flare a case TOO much, and even enough to crack the brass sometimes. With straight cases you can flare the mouth so large the case won't enter the seating die! Careful adjustment is required, at first.

You want the minimum amount of flare so that you can just "start" the bullet straight in the case mouth. No more, as that just works the brass unnecessarily and leads to premature cracking.

this bent the threaded portion of the Expander-Decapping rod. I contacted RCBS about the best way to straighten it, but I can order a replacement cheap from the... Tropical River company.
Click to expand...

What did RCBS say? Usually the die makers are very good about sending replacement parts, especially expander/decapper stems, and often at no charge to you.

I'd expect RCBS to take care of you, and wouldn't get anything from anyone else (where I had to pay for it) until after I was sure RCBS wasn't going to send the needed part(s).


RCBS used to do that, have things changed??
 
Not as good as the caliber-specific M-dies because the Lee die's resulting conical flare does not keep the bullet straight and upright as the M-die expanded profile does. Keeping them upright and straight reduces finished cartridge runout considerably and that has a measurable effect on group size.

That said, I have one of the Lee dies in case I run into a problem in a caliber I don't have an M-die for. But if I'm going to shoot that caliber much, I soon have an M-die for it.
 
Arsenal new 30 caliber match cases have their necks expanded about .0015" larger than the 173-grain FMJBT match bullet's .3086" diameter. At the shoulder junction, inside diameter was about .3076". A sealant was smeared inside the neck before bullets were seated. That "doughnut prevented the bullet from falling further into the case. The sealant hardened and "glued" the bullet in place then needing at least 20 pounds of force to push or pulling it out.

Explains one reason why that ammo had .006" or more bullet runout.
 
On the other hand, I expect the seating dies explain a lot of it. I've had 168-grain MatchKings in LC 30-06 brass that was resized in a standard FL sizing die (no loose neck or pitch sealant involved) come out of a standard Redding seating die with 0.008" TIR. Going to Redding's Competition seater cut that TIR by a factor of 4. The LC cases averaged about 0.002" neck wall runout, which likely accounts for what remained.
 
Update

So first things first, they are sending me a part, the threaded rod that the expander plug and decapping pin screw onto. On my bent rod, I was able to *sort of* straighten it out. It'll deprime but there's some run-out and I bet the case mouth opening isn't expanded into an exact circle. I think their replacement will fix this and I doubt my expander plug was damaged.

Here's a follow-up message I sent them after I realized I didn't actually explain my problem, just that the threaded rod was bent.

"Question: I am trying to load hard cast lead projectiles in my 300 blackout, and have a 2 Die small base set. Is there anything that can expand/flare the case mouth so the lead projectiles will fit (and not shave the powder coating off)?"

Their response was:

"What is your case lead bullet diameter? We offer a neck expander for rifle/ bottle neck. "

Case lead bullet diameter? First I've ever heard the term but I'm new to rifle. Do they mean bullet diameter at the base of the projectile, or inner diameter of the case mouth? :confused:
 
Plus one for a Lyman M die in the appropriated caliber. I use it for both cast and jacketed bullets, and get better accuracy having done so. Rod
 
I just ordered the Lyman M die, (I don't have the heart to tell the RCBS technical help guy), we'll see if it works.
 
What you want to do when you have that M-die is stop using the expander in the FL resizing die. It is well-documented that expanding by withdrawing the case over an expander ball will pull case necks off-axis with the rest of the case while pushing an expander into the case is much less disruptive. In the latter case, the cone of the shoulder is correctly oriented to provide much better rigidity in opposition to the expanding force. To prove this to myself, I once sized 20 .30-06 cases the normal way, then removed the expander and sized 20 more, then reinstalled the expander and expanded the necks by pushing the cases just far enough into the die to get the job done. On a runout gauge, the necks from the second group were straighter, but I no longer recall the numbers.
 
Thos3 have you that haven’t loaded 300 bo, may not have the same issues. 300 bo has more neck thickness variation due to the number of converted brass in use, I think.

In addition, light 30 cal bullets are pretty flat base.

I had to just kiss the case mouth with my Lee expander die to get bullets to start. No further trouble after that!
 
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