Neck tension, expander ball or Not?

The expander ball makes the brass round again. Brass can get bent out of shape pretty easy.
It would depend on how many times the case has been re-loaded as to just what that case may need. Proper annealing can bring back case life and give more loads. It also puts the spring back into that brass and will help with case neck tension. De-capping pins get broken from time to time. You may find that a primer hole was not where it should have been and that could be what broke that pin. A loose pin will get broken soon than later.
I recently saw primer holes in some "Perfecta" .223 brass and about 50% of them had primer holes that were not even close to center. We too broke a pin right away. That brass went in the scrap bucket.
Annealing done right will create nice usable brass and give very nice results. Done wrong and it will ruin the cases.

When you get time check different brass to see if the mic out the same way. Mil spec brass is thicker and will give a different set of numbers sometimes. But as a rule they should mic out the same after sizing.
.004" is likely good. If you cannot push the bullet back by hand it has case tension. If you can it is too sloppy.
Most AR .223 brass needs no crimp and that holds pretty true for most .308 rounds too. Case tension should be more than enough to allow function in any autos.
I have never crimped any .223 or .308s even in my bolt guns. Using match bullets there is no crimp groove anyway. Some will attempt to tapper crimp when it is not needed.
If you want more tension, I have polished the expander balls to reduce their size a tad and make them smoother. I use my lathe but it could be done with a drill and very fine sand paper. Wet sand paper like maybe 1500 or even 2000 grit will polish and yet remove some if you stay at it. It takes a lot more than one may think to reduce their size.
You are ahead of the game because you already know what is going on with your brass. That is a good thing. Keep it up.
Slide just the expander ball up to a .308 case mouth and see if it pushes in by hand. It may be out of spec. Polishing may work.
Good luck.

Don't remove the expander ball from a standard FL die. Its job is to expand squeezed down necks to a mouth diameter good for bullet diameters. If it isn't there the case mouth will be too small and cause:

* bullet jacket to be peeled off unbalancing the bullet.

* too tight and uneven grip on bullets raising pressures and increasing velocity spread.

Put the expander ball back in the die.

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Die's used without expander balls have their necks larger than dies using expander balls. Such necks are about .002" smaller than loaded round neck diameters. Not .005" to .006" smaller like standard full length sizing dies.

Try this: measure the bullet OD and the case neck ID after sizing. Seat a bullet. Pull the bullet and measure the case neck ID and the bullet OD. I'll bet the case neck ID is now 0.001-0.002" smaller than bullet diameter. This is because the bullet expanded the neck or the neck swaged the bullet diameter down.
The extra effort can push the bullet crooked. Proper expanding makes bullet seating easier and less bullet turn out. Not expanding does not increase bullet tension.
I always use a FL size die, adjusted until the cases just chamber easily (minimize shoulder push-back) and have never really seen a need for neck sizing as I don't shoot 0.4 MOA groups.

noylj said:

Not expanding does not increase bullet tension.

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If that's true, why does it take more force to pull a bullet out of a case neck that has a .0010" interference fit than one with a .0001" interference fit?

The industry standard is the release force needed to push or pull the bullet from the case neck. It's measured in pounds. The difference between case mouth and bullet diameter is called an interference fit. Depending on the elasticity of the case neck and friction between it and the bullet, the same amount of interference fit can result in different release force needed.

Higher release force causes higher muzzle velocities. I've seen a few instances of people removing expander balls to increase bullet or neck tension and get very flattened primers. Proof that peak pressure went heavenly high. Same as seating bullets to chamber against the rifling; more force needed to get the bullet moving, pressure goes up.

Wildfire said:

Slide just the expander ball up to a .308 case mouth and see if it pushes in by hand. It may be out of spec.

Click to expand...

All my 30 caliber expander balls are about .307" diameter.

If it goes in easy, is it out of spec?

You need the expander ball. Bullets are not intended to serve as a substitute for one.

I would talk to redding before you buy a bushing die. Unless you're using premium brass, you're wasting your time.

Short of any gross issues, the impact that your sizing die has on accuracy is going to be very difficult to distinguish from "zero."

30Cal said:

I would talk to redding before you buy a bushing die. Unless you're using premium brass, you're wasting your time.

Short of any gross issues, the impact that your sizing die has on accuracy is going to be very difficult to distinguish from "zero."

Click to expand...

There are people that have and do all the right stuff to prove otherwise.

Joshboyfutre said:

Lee full size die

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Lee die expander get pulled off easily, I guess that is why many don't want to use it. My RCBS 308 die expander measures .3065" but Lee is .307", polish it down to .306" helps a lot.

Bart B. said:

If that's true, why does it take more force to pull a bullet out of a case neck that has a .0010" interference fit than one with a .0001" interference fit?

The industry standard is the release force needed to push or pull the bullet from the case neck. It's measured in pounds. The difference between case mouth and bullet diameter is called an interference fit. Depending on the elasticity of the case neck and friction between it and the bullet, the same amount of interference fit can result in different release force needed.

Higher release force causes higher muzzle velocities. I've seen a few instances of people removing expander balls to increase bullet or neck tension and get very flattened primers. Proof that peak pressure went heavenly high. Same as seating bullets to chamber against the rifling; more force needed to get the bullet moving, pressure goes up.

Click to expand...

the thickness of the case neck also affects the release force (why i turn case necks in cheap cases).

anything that increases the release force (e.g. tighter press fit (same as interference fit), cleaning the inside of case necks, longer case necks, work hardened case necks, thicker case necks (google "hoop stress" for why)) increases the inertia of the bullet and, therefore, increases the pressure and velocity of that load (same as increasing the bullet weight without reducing the powder charge or shoving the bullet into the rifle lands).

this is why i think case prep is the most important step in the handloading process.

i'm agreeing with bart b. here, by the way!

murf

p.s. the inertia of the bullet does not increase, per se, but all these resistant (friction) forces add to the effort to "get the bullet moving down the barrel".

Bart B. said:

Don't remove the expander ball from a standard FL die. Its job is to expand squeezed down necks to a mouth diameter good for bullet diameters. If it isn't there the case mouth will be too small and cause:

Click to expand...

Bart put his finger on exactly why dies with expander plugs are about a century out of date and utterly obsolete. for reloading bottleneck rifle calibers. Modern bushing dies, with correct size bushings, make the neck the right diameter to begin with.

Bart B. said:

There are people that have and do all the right stuff to prove otherwise.

Click to expand...

Got a reference? All I've been able to find with google are anecdotal accounts or benchtop measurements, but not actual targets.

When I spoke with Redding the answer for LC/Win/Rem brass was "don't bother with a bushing die unless you plan on getting into neck turning".

Regarding Offhand's post #14........

Or good full length sizing dies whose necks are about .002" smaller than ammo's neck diameters. These were the best some years before bushing dies. They tend to make case necks better centered on case necks and bodies than bushing dies do; bushings have a tiny bit of slop in their dies. Small difference only noticeable in rifles with best accuracy.

Regarding:

30Cal said:

I would talk to redding before you buy a bushing die. Unless you're using premium brass, you're wasting your time.

Short of any gross issues, the impact that your sizing die has on accuracy is going to be very difficult to distinguish from "zero."

Click to expand...

Where I answered:

There are people that have and do all the right stuff to prove otherwise.

Click to expand...

Then was asked

Got a reference? All I've been able to find with google are anecdotal accounts or benchtop measurements, but not actual targets.

Click to expand...

Yes, here's a reference.

Last time I talked with Sierra Bullets about their test criteria for quality of their bullets, the rep said they used Redding full bushing dies for cases they're made for. Using unprepped nor sorted Remington and/or Winchester cases, their best match bullets shot 1/4 MOA average in their 200 yard range. That's what the best benchrest rifles do. Call them then ask yourself.

Here's another:

What type of case sizing and/or prep was done to shoot this group?


Which of these two 15 -shot groups were shot with new, unprepped cases? Which one was shot with once fired, unprepped but neck turned and full length sized cases? X-ring's 10 inches diameter.



Here's 3 questions for you:

If a case neck has wall thickness spread of .002", how far off center will its mouth be coming out of the neck of a sizing die and not expanded by a ball?

What's the realistic maximum bullet runout number for a cartridge to have best accuracy?

Why did benchrest folks start switching from neck only to proper full length sizing with gelded full length sizing dies (those without balls) minimally shrinking fired cases some years ago? Surely the die's made a difference they know about. Sierra bullets learned that back in the 1950's.

30Cal said:

Unless you're using premium brass, you're wasting your time.

Click to expand...

30Cal said:

Got a reference? All I've been able to find with google are anecdotal accounts or benchtop measurements, but not actual targets.

When I spoke with Redding the answer for LC/Win/Rem brass was "don't bother with a bushing die unless you plan on getting into neck turning".

Click to expand...

Wow! That's quite a statement. The consulting firm I work for (part time) often deals with the folks at Redding and I can't imagine anyone there saying such a thing. Next time I'm there I bring this up and simply ask who would have said that to a customer. I'm sure they will be as surprised as I am.

Redding's top man and I had a discussion about the unsized 1/32nd inch portion of case necks (I call a mini shoulder) next to case shoulders their bushings do not reduce.

His contention was that mini shoulder helped center the round in the chamber neck.

My contention was it's always smaller than chamber necks so there's no way it can center the case neck at that point. He could not comprehend the case shoulder centering in the chamber shoulder centering the case front end in the chamber shoulder from firing pin impact. When I said a .243 Win case neck would perfectly center in a .308 Win chamber when fired, he chuckled.

Bart B. said:

Redding's top man and I had a discussion about the unsized 1/32nd inch portion of case necks (I call a mini shoulder) next to case shoulders their bushings do not reduce.

His contention was that mini shoulder helped center the round in the chamber neck.

My contention was it's always smaller than chamber necks so there's no way it can center the case neck at that point. He could not comprehend the case shoulder centering in the chamber shoulder centering the case front end in the chamber shoulder from firing pin impact. When I said a .243 Win case neck would perfectly center in a .308 Win chamber when fired, he chuckled.

Click to expand...

If the "mini-shoulder" can't center in a chamber, why would a 243 center any different in a 308 WIn chamber?

It's all based on the Dixie Cup Syndrome. Dropping one cup into another ends up with the inside cup (case shoulder) perfectly centering in the outside cup (chamber shoulder). Their center axes are perfectly in line with each other because their mating surfaces have the same angle.

The 243's shoulder's angle is the same as the 308's. There a lot more clearance from the 243's neck to the 308 chamber's neck than a 308 case has but they're both centered on the cartridge's long axis. Dropping the 243 case into the 308 chamber ends up with its shoulder perfectly centering in the 308 chamber's shoulder. So does a small circle (case neck location) centered on the bottom of that inside Dixie cup have lots of space to the outside Dixie cup's bottom as they're both centered on the same axis. Ditto with 260 Rem, 7-08 Rem and 358 Win chambers.

25-06 rounds do the same thing in 270 Win, 30-06 or 35 Whelen chambers. All have the same shoulder angles.

Meanwhile, standard full length sizing dies squeeze case necks down all the way to their shoulder. They'll size down those "mini shoulders."

Sooo...If it's not centered at the shoulder, it doesn't really matter what the neck is doing? (In terms of centering)

Yes, but remember those cases center in the chamber when they fire because the firing pin has driven them hard into the chamber shoulder where they stay perfectly aligned while the round fires. The force is enough to set the case shoulder back a few thousandths inch or more increasing case head clearance to the bolt face

Of course, if the neck's off center on the shoulder, so is the bullet.

Okay, I see now, the guy tried feeding you a line of bull. The function of the bushing die, while convenient, can build a "doughnut" and he tried to put a pretty face on it. Fantastic.

Back to the OP though, I think he only read half of the relevant content where it comes to removing the expander ball. You know, that bit about needing to hone your die neck to an appropriate tolerance.