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Old May 19, 2020, 09:54 PM   #1
burbank_jung
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The expander ball

Someone commented on one of these recent posts about avoiding the use of the expander ball to reduce concentricity problems. I once read that this contributed to stretching the case neck but not concentricity.

Sometimes we Reloaders are so anal about the small details it's like pulling hairs ( anyone getting bald out there? ). But here's the question. How do you avoid it? Can I use imperial wax or maybe the Lee collet die?
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Old May 19, 2020, 10:02 PM   #2
pwc
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Some say, if the xpander is not concentric it will pull the neck to one side. Supposidly using a rubber "O" ring helps prevent this.

Neck tension with or without xpander is another discussion.
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Old May 20, 2020, 08:16 AM   #3
zeke
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First you may want to test one of your loaded rounds for concentrically. If lacking a specific tool to do this, simply roll the loaded round on a flat surface and eyeball it at it's level. If you can see it wobbling, you might want to consider making your rounds more concentric.

You can try to minimize it on some dies by using carbide expander, loosening the lock nut on the expander and allowing it to "float/self align", taking off the expander ball and using a plug type expander, not using an expander at all (with certain other variable adaptations) or other techniques/combination of techniques.

If your die allows it, the easiest/cheapest way may be to allow your expander to slightly free float. If using this technique, consider squaring up your re-sizing die first.
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Old May 20, 2020, 09:27 AM   #4
pwc
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Whem you size; lower the ram, rotate the case approx 120°, raise ram, hold 5 sec, lower and rotate again.
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Old May 20, 2020, 11:52 AM   #5
Bart B.
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Good info in this thread

https://thefiringline.com/forums/sho...17#post6796217
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Old May 20, 2020, 12:03 PM   #6
Bart B.
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Quote:
Originally Posted by zeke View Post
If your die allows it, the easiest/cheapest way may be to allow your expander to slightly free float. If using this technique, consider squaring up your re-sizing die first.
How does squaring up the full length sizing die improve case neck's alignment to the body?

I see no way to make that happen as the die's neck to body alignment cannot be changed.
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Old May 20, 2020, 12:34 PM   #7
zeke
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If you are going to self align the expander, it helps to ensure the case body is also self aligned (squared) on same axis. While you may not accept the concept of squaring your dies, it is/has been used in various texts for a very long time. The original post is about the expander plug pulling the neck out of alignment, and it is a fact that it can happen.
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Old May 20, 2020, 01:29 PM   #8
Unclenick
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Here is a video comparing a Hornady die with its conventional expander to a Lee Collet Die that sizes only the neck (you can size the body separately with a Redding Body die). You can see the runout from withdrawing the neck over the expander. Squaring a die, assuming your press doesn't produce self-alignment, won't help with this because it is how square the underside of the shell holder deck keeps the case aligned with the expander as it pulls down on the rim that matters. If you get a case with a dented or uneven rim that doesn't bear perfectly evenly downward, you are out of luck. The only press I am aware of that attempts to correct this is the Forster Co-ax press whose sliding shell holder plates can slip to self-align. Its floats dies in a slot, retained by their lockrings, so they are free to self-align, too.

I've tried the o-ring trick on a conventional press without much luck. The problem is the geometry of die threads isn't really right for this. You would want the die threads to be through the middle of a ball joint that can realign the die mouth on the shell deck on the fly. Instead, they are triangular profiles that don't mate evenly when the die tilts, so they try to line back up with one another as much as with the seating of the die on the deck.

One thing you can do to help with pulling the neck off-axis to use a carbide expander ball. RCBS makes them, including one that fits Redding dies, too. The first time I tried this I got an immediate improvement. I think it is mainly because the contact area is shallow so the case can be off-axis with it without much effect.

Another thing you can do is size the mouth pushing down. If you think about the geometry of a shoulder, it will be stronger resisting something pushing into it (like seating a bullet) than it is resisting something being withdrawn from it. So you can get tools like the Lyman M-dies for rifle calibers and not only expand without bending the neck but additionally can add the little step at the top of those dies just a short distance into the mouth so bullets you place there for seating stay straight up and enter the seating die ram straight. This does a lot to mitigate finished cartridge runout.
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Old May 20, 2020, 02:14 PM   #9
Bart B.
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When perfect ammo components must be perfectly aligned, how much larger than bullet diameter is its guide in the seater die?

How crooked can a .308" diameter bullet be in a 311" die guide?
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Old May 20, 2020, 03:17 PM   #10
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If you are that worried about it Bart go with a Wilson inline die. Both the .223 and the 6.5 have bullet seating guides .0005 larger than the bullets diameter.

Irony being is that it just don't matter. I seat my .260 Rems using a Forster micro .308 Win seating die. Still get very low runout. I tested out the inline die when I bought my arbor press. Seated 20 with the inline, 20 with the 308 Win die, checked all on gage the shot them in five shot groups at 600. Groupings could not be told apart.

If that case is prepped right that bullet will follow the path of least resistance into that case. The bullet is being pushed straight down by the seating die cone there is no lateral force being induced to force the neck or bullet out of parallel. The key is a straight neck with a slight inside chamfer
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Old May 20, 2020, 04:45 PM   #11
zeke
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Have used the Lyman plug expanders for jacketed bullets loads, but used a smaller dia one than the neck, which didn't expand the neck for a cast bullet, but did bell the case mouth. An immediate improvement in concentrically was observed using a standard seating die. There is another manufacturer that makes these plugs, but have forgotten.

IMO using the redding carbide (or whatever it made of) plug on their dies works so well not to pull the neck off because it is free floating. The RCBS not as much. The regular pull through plugs are locked down, but can self align some if not locked down. Some have advised letting the expander free float, till it enters the neck, then lock it down.

On most regular sizing dies the neck does not get expanded till after the brass is either full length or neck sized. If going to the trouble to not pull your necks off, would again advise to square your sizing die. If you want to debate about the benefits of squaring your dies at all, have at it. You are not debating me, but scores of others in reloading/shooting business with much more experience.

https://www.facebook.com/USAMU1956/p...707187509734:0

http://bulletin.accurateshooter.com/...-seating-dies/

https://www.sinclairintl.com/guntech....htm?lid=16099

Squaring your dies provides the self aligning benefit of a forester press without spending the money. Squaring the dies helps to self align it vertically and horizontally, and will recommend it for any function used by a sizing or some seating dies. Yet another manual that describes this is Sierra's 5th edition page 153. IT COSTS NOTHING

Actual experience has taught me not to assume the outside of a die is in line with the inside.

A very good point about the nicks in a rim, especially from semi's. Have found the vertical force from the full length re-sizing process on semi auto brass helps mitigate that.

Other advise is to get a decent comp seating die.
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Old May 20, 2020, 05:48 PM   #12
Bart B.
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My bullet seaters....

Wilson BR chamber type .308, circa 1966;.3105"
RCBS standard .308, circa 1966; . . . . . . . . .3100"
RCBS standard .308, circa 1979; . . . . . . . . .3115"
RCBS competition .308, circa 1980's; . . . . .3107"
RCBS standard .300 Win Mag, circa 1999, .3104"
RCBS standard .30-.338, circa 1967, . . . . . .3102"
Bonanza BR .30-.338, circa 1980; . . . . . . . . .3093"

30 caliber bullet diameters I've measured go from .3070" to .3092".
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