Expander ball fact or fiction

[Boozer]

I've been looking into the topics of neck tension, concentricity, and thickness lately. Right now I use Redding FL deluxe dies (non-bushing) and am not interested in taking the plunge into the world of neck turning and bushing dies just yet.

I'm hoping that folks here can confirm some trends that I'm beginning to see in articles, forums etc. Please let me know if any/all of these methods have helped you increase brass life, decrease groups sizes, etc. many of the things I've read will say "this really reduced my case run-out" but at the same time "my groups didn't improve". With all the steps involved in reloading, I'm not terribly interested in doing things that help only in theory, and not in practice.


Polish the expander ball - I think this one is a commonly accepted practice, idea is to reduce resistance of pulling the ball thru the neck, reducing induced stress, and helping concentricity.

High position expander ball- Some dies (forester I think) are sold with an expander ball mounted high in the decap rod. I believe the idea is that as the case is being withdrawn from the dies, the case mouth is still in the necking portion of the die, while the bottom is starting to be drawn through the expander ball. supposedly this supports the case, and aids in concentricity. Since I decap as an independent operation, I think I can unscrew my decap rod to the point where this operation is the same (or close). My Redding also has a floating expander ball, so I think this helps, very similar to having an o-ring under the decap lock-ring.

Larger/Smaller expander ball and/or die honing- It's fairly common knowledge that std dies, undersize on the upstroke, and open back up on the down stroke, to a given ID. In order to accommodate all different neck thicknesses, std. dies waaaaay undersize on the upstroke, and open up to varying amounts as the expander ball is pulled through, providing inconsistent neck tension.

Some folks are custom ordering larger expander balls to reduce neck tension to .002-.001 etc. for better accuracy, and others go a step further in honing the neck sizing portion of the FL die so that it doesn't size the brass so small to begin with, likely increasing brass life due to not overworking it so much, and decreasing run-out because every time you resize it's only moving the brass tiny amounts.

"Cleaning up" neck thickness- Since I shoot a SAAMI chamber rifle with a std. neck, turning the neck to a reduced size is not desirable. Some folks in my shoes are adjusting their neck turn tools, to the point that they are only cutting 60-70% of the neck surface, effectively capturing the majority of the benefit, without the drawbacks associated with having a case-neck that's too small for the chamber. consistent neck thickness equates to consistent tension, and even release on the bullet.

Thanks

BB

 

[bigedp51]

I prefer Forster full length dies with the high mounted floating expander. This system greatly reduces neck runout and I have replaced all the expanders on my RCBS dies with the Forster expander and spindle assemblys.

Below a RCBS FL .223 die with the Forster expander and spindle assembly. The thick rubber washer allows the spindle to float and self center in the die. The neck of the die holds and centers the case neck as the floating expander enters the neck and the expander can not pull the case necks off center and induce neck runout.

Polishing the expander and using powdered graphite inside the case necks greatly reduces friction.

At the Whidden custom die website they tell you they get the least amount of neck runout with standard non-bushing full length dies. They also sell expander sets with 5 different expand diameters.

We live in a plus and minus manufacturing world and chambers and dies vary in size.

Are Your Sizing Dies Overworking Your Rifle Brass? - MassReloading

I bought a Forster FL .223 die with the intentions of having the neck honed but the neck diameter of the die was large enough that honing was not required. The die was working the brass less than .003 which was far less than any of my other .223 dies.

FL Bushing Dies vs. Honed FL Dies

http://www.accurateshooter.com/technical-articles/reloading/fl-bushing-dies-vs-honed-fl-dies/

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[FearNoWind]

... am not interested in taking the plunge into the world of neck turning and bushing dies just yet.
... Since I shoot a SAAMI chamber rifle with a std. neck, turning the neck to a reduced size is not desirable.
... I'm not terribly interested in doing things that help only in theory, and not in practice.

Polish the expander ball
The amount of stress reduction experienced from polishing the expander ball depends on two factors. 1. How much better it is polished than it was originally 2. How much debris (carbon) is caked inside the neck to drag (friction) on the ball during expanding operations.

High position expander ball
Full length sizing dies usually include an expander ball on the decapping rod. The models that use a "floating" expander ball are intended to be "self centering" in the case neck, and the theory is that the case neck guides the ball instead of vice versa. But if the ball self centers in the case neck and the case neck center line is not perfectly aligned with the center line of the case (and that's quite common - hence neck turning; but we'll get to that later) then all is for naught.

Larger/Smaller expander ball and/or die honing-
I believe what you mean here is that case neck passes over the expander ball, then it undersized as it passes in and out of the neck sizing area of the die, and is once again expanded as it makes its second pass over the expander ball. That's a common feature of full length sizing dies. It tends to "over work" the brass and that's something most reloaders would prefer to avoid. Honing the die simply means that you're removing some of the surface of its interior (usually using a steel rod of appropriate diameter, some abrasive material and a lubricant) but it requires a lot of work to do that job correctly and doing it incorrectly can produce an out of round neck sizing operation.

"Cleaning up" neck thickness-
OK, now let's get to neck turning. I know; it's not your favorite subject. But stay with me on this one.
You appear to have the opinion that all or nearly all of the sizing operations involve the inside of the case neck. Squeeze if down and expand it back out. All things being equal, I'd saythat's pretty much true. But when cases are manufactured their neck thickness commonly varies throughout the circumference of the neck. To make an exaggerated point - if a case neck is .005" thick on one side and .002 on the other, no amount of honing, neck expander ball polishing or other adjustment will ever produced consistent runout. The runout will always vary by .003. The only way to correct that error is to turn the case neck so that its thickness is uniform overall.
Taking it one step further, if your case neck thickness is not uniform there is no way you will ever achieve uniform neck tension.
Is it bad? - of course not. Rifles shoot very well without a lot of fuss about uniformity of neck tension/runout. But they shoot better when some attention is paid to the finer details of reloading operations.

 

[bigedp51]

Boozer

The Forster expander does not float on the spindle assembly, the spindle shaft floats and self centers with the case neck centered in the neck of the die.

And you can't make a silk purse out of a sows ear and neck turning will not center the bullet in the case if it does not have uniform case wall thickness.

A full length resized case is supported by the bolt face in the rear and by the bullet in the chambers throat. The body and neck of the full length resized case does not touch the chamber walls. And only the shoulder of the case is touching the chambers shoulder being pushed forward by the ejector.

Bottom line, neck turing does not center the bullet in the throat and only effects bullet grip uniformity.

Too much of what benchrest shooters do with their custom rifles with tight neck chamber filters down to us and is not needed.

If you reduce the neck diameter .005 or more with bushing dies you will induce neck runout. If you do not neck turn you still need to use the expander with a bushing die.

The greatest stress on your case neck is expanding to the neck diameter of your chamber when fired. And resizing the case neck is a minor part of the stress put on the case neck.

Your factory rifles have SAAMI chambers and your factory dies are made to SAAMI dimensions. So lube the inside of your case necks and forget all the hype about expanders being the worst thing in the world for your brass. And again Whidden custom dies tells you they get the least amount of neck runout with a standard non-bushing full length die using a expander.

If you want more uniformity with your brass then buy Lapua.

In the photos below is a average Remington .223 case with .004 neck thickness variation and some of the cases had .008 neck thickness variation.

The military considers match grade ammunition to be .003 or less runout. And Forster dies will produce the least amount of neck runout of any die.

 

[Mikecr]

All these poor ideas result from a simple reality:
Crooked ammo works better in a sloppy chamber.

This is the tail chasing behind FL sizing -for SAAMI chambers -and poorly designed cartridges.
Go to a tighter chamber, for a better cartridge, and FL sizing is no longer beneficial or needed.
With this scenario, discussions about making straight ammo actually lead to it.

 

[oldfortyfiveauto]

Another issue caused by the expander ball I've not seen discussed is what the expander ball does to the case shoulder when it is withdrawn. The larger expander balls will actually pull the shoulder out as it is withdrawn effectively making the case longer (changes headspace). For that reason I often use an expander mandrel to control neck tension.

 

[FearNoWind]

Another issue caused by the expander ball I've not seen discussed is what the expander ball does to the case shoulder when it is withdrawn. The larger expander balls will actually pull the shoulder out as it is withdrawn effectively making the case longer (changes headspace). For that reason I often use an expander mandrel to control neck tension.

That's an excellent point, IMO. I remove the expander ball from my dies and use an expender mandrel to round out the necks after full length resizing. Also the Redding type S bushing dies help me control neck sizing far better than the
Another excellent point made elsewhere in this thread is that working with an off the shelf hunting rifle with SAAMI spec. chambers the finer details that a lot of us go to in perfecting the reloaded ammo to shoot .25 moa or less isn't really necessary IMO; at least not for a hunting rifle where any rifle capable of holding under 1 moa in the hands of an accomplished marksman should be enough.

 

[86alaskan]

I use the expander in all my dies. I have spun them in emery cloth to make them as smooth as possible but that's all. I make sure to adjust my dies to do the minimum amount of shoulder bump necessary for proper reliability. As others have stated, the expander is not the enemy for a factory chamber. Use it and just make sure everything is as it should be and your ammo with come out fine.

 

[Pdvdh]

Boozer

And you can't make a silk purse out of a sows ear and neck turning will not center the bullet in the case if it does not have uniform case wall thickness.

What am I missing? This schematic portrays the casing after neck turning, but prior to fire-forming the neck-turned casing.

After fire-forming the neck-turned case in the rifle, the center of the neck will become the center of the casing too. Unless the rifle chamber isn't cut concentric to the center of bore.

 

[Boozer]

Lots of good stuff happening here.

To clarify, I should note that my rifle has had the action trued, and been rebarreled with a bartlien 5R by a very reputable smith here in KC. Though the chamber is SAAMI, it was done with a reamer at SAAMI minimums, so this isn't your typical sloppy ol factory job. Though I don't want to discourage folks bringing up these points because all the comments are valuable to others who will ready them later. The rifle is serving double duty as a hunting rifle and target rifle. I am planning to shoot my first F-class match at the end of the summer.

All that being said I understand that some of the described procedures won't have any impact on a rifle that is less than top quality.

Help me understand the use of an expander mandrel. You FL resize without an expander ball, and then go back and expand the neck to desired tension with the mandrel as a separate step? If this is right, I don't quite understand why the mandrel is a better route. What advantages do it provide over the expander ball? is it due to the force being applied downward instead of upward?

 

[bigedp51]

What am I missing? This schematic portrays the casing after neck turning, but prior to fire-forming the neck-turned casing.

After fire-forming the neck-turned case in the rifle, the center of the neck will become the center of the casing too. Unless the rifle chamber isn't cut concentric to the center of bore.

What are you missing is if you buy quality brass then neck turning isn't required in a SAAMI chamber. What I was trying to get across was the poor quality of American brands of brass like the Remington brass that varied between .004 and .008 in neck thickness.

If you go to AccurateShooter.com, F-Class shooters are using Lapua brass and do very little to the brass.

Bottom line, why bother neck turning cases with .004 to .008 thickness variation and wasting your time trying to make bad brass better.

And with a full length resized cartridge case the bullet is centered in the throat, while the rear of the case is being held by the bolt face. Meaning the clearance between the case and chamber gives the cartridge wiggle room to let the bullet self center with the bore. And it is the poorly made cases that warp and become banana shaped that cause alignment problems.

So again, much of what benchrest shooters do with their custom rifles with tight neck chambers does not apply to poor folk with off the shelf factory rifles.

 

[Pdvdh]

So your point in presenting the illustration was not to imply that outside neck turning fails to bring the center of the case neck into concentric alignment with the center of the casing.

Your point was limited to expressing your preference to purchase higher quality brass at a higher cost, rather than investing hobby activity and time outside neck turning less expensive brass into more uniform (higher quality) brass. A personal choice on how to obtain higher quality cartridge cases.

 

[bigedp51]

Help me understand the use of an expander mandrel. You FL resize without an expander ball, and then go back and expand the neck to desired tension with the mandrel as a separate step? If this is right, I don't quite understand why the mandrel is a better route. What advantages do it provide over the expander ball? is it due to the force being applied downward instead of upward?

In the Speer No.9 reloading manual there is a chapter on reloading ammunition to benchrest quality. It stated the biggest cause of neck runout was due to locking the expander down off center.

If you full length resize a case without the expander the resized case will be as straight and concentric as its going to be. If a expander is used and is off center it will pull the case necks off center.

A simple Redding case neck concentricity gauge will tell you a lot about the quality of your brass with a twist of the wrist.

And a runout gauge with tell you about the quality of of your resized brass and loaded ammunition.

I have used my Sinclair expander die to expand case necks, and I have used body dies with Lee collet dies. And in my opinion my Forster dies produce straight cases with the least amount of neck runout without having to size the cases in two steps.

So buy some quality brass and gauges to inspect your sized and loaded ammunition and see what works best for you. Just remember to lube the inside of your case necks and forget internet rumors about expanders.

Below from Whidden Gun Works.

"The non-bushing sizer die typically yields more concentric ammo in our experience. It also fully sizes the case neck fully to the shoulder for smoother functioning. Neck tension can only be determined by changing expander balls with the non-bushing die."


http://www.whiddengunworks.com/wp-content/uploads/2015/02/Bushing.NonBushingExplanation.pdf

 

[bigedp51]

So your point in presenting the illustration was not to imply that outside neck turning fails to bring the center of the case neck into concentric alignment with the center of the casing.

Your point was limited to expressing your preference to purchase higher quality brass at a higher cost, rather than investing hobby activity and time outside neck turning less expensive brass into more uniform (higher quality) brass. A personal choice on how to obtain higher quality cartridge cases.

Actually you can sort cheaper cases with a Redding case neck concentricity gauge and not waste your time turning case necks that are shot in SAAMI chambers.

This isn't Benchrest Central and neck turning and spending hours prepping brass fired in a SAAMI chamber is not worth the effort.

I buy a lot of once fired Lake City brass that will be fired in AR15 rifles or a Savage .223 bolt action. I sort these cases with my Redding neck thickness gauge. The cases with .001 or less neck thickness variation are fired in the bolt action. And the casses with .004 or more variation are used for blasting ammo in my AR15 carbine.

So again neck turning crappy brass doesn't make it shoot better in a SAAMI chamber. And you can't make a silk purse out of a sows ear.