Redding Type S bushing die: use expander or not?


July 31, 2010, 10:55 PM
I picked up a Type S full-length die in .223 and a few bushings, but I'm a little confused about how to make the best use out of it. The decapping rod assembly has an expander on it, but there's also a piece provided with the die that replaces the expander, and doesn't expand the brass.

The fundamental concept that I don't grasp is this: How do the bushings control neck tension if there's an expander that will pull back through the neck? When using the expander, are the bushings just used to prevent over-working the brass, to account for different neck thicknesses?

For reference, I'm loading for an AR-15 with a 5.56 Wylde chamber, using Lapua brass. At this point I don't do any neck turning or sorting based on neck thickness.

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July 31, 2010, 11:09 PM
When using the expander, are the bushings just used to prevent over-working the brass, to account for different neck thicknesses? Yes, most standard dies size the neck down way to much. If your loading a boatail bulllet, you can skip the expander. The bullet will become your expander. For an auto you need good neck tensions. Measure a sized case, before and after seating the bullet. With bullet seated , the neck has to expand .002" for good neck tension. This .002" is on the case with the thinnest neck wall thickness. (

July 31, 2010, 11:59 PM
Thanks for the quick response, 243.

I measured five loaded cases and came up with an average dimension of .2512" with a stddev of .00029". This coincides with some previous, informal measurements that I've done.

I've been using the .248" bushing, but until today I had been using it with the expander button on the decapping rod assembly. This would explain why I wasn't seeing consistent results from tests between different bushing sizes - the expander (rather than the bushing) was responsible for setting neck tension.

Is it still kosher to go without the expander even if I'm not uniforming my necks? I suspect that I'm fine with new Lapua brass, but what about after a few firings? What about something like Lake City?

August 1, 2010, 12:43 AM
When you have a large variation or unknow neck wall thickness, its best to use the expander. You must choose the correct bushing so as to not over work the brass. Some of my neck turned brass thats been loaded 15 to 18 times have started to get a variation in neck wall thickness, not using an expander. I went to a .001" smaller bushing to make up the difference. A lot of neck tension is not needed for a single shot, bolt gun. Another thing you have to watch out for thats posted on Reddings website is, when your bushing has to size the fired case down more than .008" or more, the neck will be smaller than expected for that bushing. From Redding tech line> It has come to our attention through customer calls and our own use of the bushing style sizing dies that in certain instances, a given neck sizing bushing will produce a case neck diameter that can be several thousandths of an inch smaller than the actual diameter of the bushing. This idiosyncrasy occurs when the neck diameter of the fired case is a great deal larger than the diameter of the neck sizing bushing, such as occurs when factory chambers are on the large side of the tolerance range and the brass is on the thin side. Typically, we have not noticed any problems until the case neck is reduced more than 0.008-0.010".

Solutions include, increasing bushing diameter to compensate and/or the use of a size button. Reducing the neck diameter in two smaller steps by using an intermediate diameter bushing will also help. More concentric necks will also result using this method, as the case necks are stressed less during sizing. Don't forget to properly chamfer the inside and outside of the case mouths and apply a light coating of lubricant to the case necks before sizing.

August 1, 2010, 11:09 AM
I use the expander. If you select the correct size bushing, you shouldn't be working the brass much at all pulling the expander through the neck. In my opinion, the expander helps to make neck tension more consistant between individual peices of brass.

August 1, 2010, 11:17 AM
Take a tip from the benchrest shooters. They are the most exacting, accuracy minded shootars and reloaders on the planet. They invariably use sizing bushings (usually carbide) and I've never seen even one of them use a neck expander. I once asked one of the top experts about this and he told me expanders are a curse and should be outlawed.

August 1, 2010, 11:55 AM
Well, I guess if everybody agreed on the best approach, we wouldn't need a discussion forum. :)

August 1, 2010, 12:11 PM
I agree with offhand, expanders are definitely not needed and should not be used with bushing dies. Just get the right size bushing.

August 1, 2010, 12:17 PM
In a bushing die the only thing the expander does is undo what the bushing just did. If you want .002 neck tension you use bushing X if you want .001 neck tension you use bushing Y, no expander needed. I mean what's the point of using different size bushings if you make the necks all the same with the expander? Save the brass for maybe 1 or 2 more firings? not.

August 1, 2010, 12:26 PM
If the thickness of the neck walls vary, without an expander, so will neck tension.

August 1, 2010, 12:28 PM
Expander will make no difference.

August 1, 2010, 01:05 PM
Walk, I don't doubt you know what you're talking about. Logically, wouldn't pulling a fixed dimension object through an orifice, (that is slightly larger than the orifice), on several objects, bring them to the same inside diameter? {Given the walls are reasonably uniform in thickness and composition). Making them the same I.D. would make the bullet pull the same as well. What am I missing?

August 1, 2010, 01:41 PM
Bench rest shooters outside neck turn there brass. no expander is needed. If you do not turn your brass and wall thickness is constant you can get away with not using an expander. It helps seating if your using a boatail bullet. When you have necks with a different degree of thickness & untured, loading a flat base bullet, you will have to use an expander. :uhoh: Remember he is > loading for an AR-15 with a 5.56 Wylde chamber, :scrutiny:

August 1, 2010, 01:42 PM
If you do not turn the brass to make it uniform it will spring back slightly different no matter which direction you are moving it.

The best use for bushing dies (IMHO) is for tight necked chambers where one reams and/or turns their necks to a very consistent thickness to match their chamber.

That does not mean they can not be used successfully for standard chambers (even if "match" chambers) with quality brass. They can, and are. Many who are are using the best brass available (Lapua), which will be very consistent (as unprepped brass goes) to begin with. Many of them still neck turn to get it even more consistent.

There are so many things that make a great deal more difference on target than slightly different neck tensions. (Wind, shooter error, etc.)

Master those things and then you will begin to be able to take advantage of things that can put you in the top 10% vs the middle of the pack. First though, you must be capable of running with the big dogs.

1858, U.S.S.R. & others can answer to the long range stuff better than I can. My game was 100 & 200 yard Benchrest. Some things that we could get by with at those yardages (Mainly a bit bigger ES & SD numbers), you cannot at 1000 yards.

I bet shooting at 1K is a blast. Probably as frustrating as trying to shoot zeros at 200 at times, but a blast overall. :)

No need for an expander with flat base bullets, which was all we shot in BR. No expanders. A slight chamfer is all that is needed. Some used such light neck tension, even a chamfer was unnecessary.

August 1, 2010, 01:58 PM
Fatelvis -What am I missing? Neck turned brass inside diameter(ID) only needs to be .001" smaller than bullet diameter for a bolt action bench rifle. On seating, the bullet can do the job of the expander without having its nose/ogive deformed. A boatail starts into the case mouth better. If the ID is .003" smaller than bullet dia. the boattail bullet will still expand THE neck on seating. THE BULLET CAN BE THE EXPANDER :)

August 4, 2010, 04:52 PM

Yep. I made this point to guys who say "bushing dies should only be used with brass with turned necks". They would say that "the bushing pushes all the neck wall thickness variations to the inside of the neck". I simply countered with the fact that the insertion of a bullet pushes them right back out to the outside of the neck.


August 4, 2010, 07:34 PM
I simply countered with the fact that the insertion of a bullet pushes them right back out to the outside of the neck.Exactly.

August 5, 2010, 12:05 PM
I struggled for years on a quest to get a 1" 5 shot group at 100 yards throughout the 1990s.
When I finally got the important variables under control [and not some of the subtle stuff I read about on the internet, usenet in the 1990s], I started getting groups smaller than 0.5".

One of the key variables was that expander balls can pull the neck crooked. Almost nothing can fix a bent case neck, except firing it again.

The expander ball makes the neck crooked when the expander ball is used in the same step as a sizing die with smaller than needed neck. The expander ball goes through the neck on the push stroke without touching, then the case neck gets sized very small by the neck of the die, then on the pull stroke the expander ball pulls on the inside of the neck and expands the neck. The shell holder to rim connection does not pull concentricly with the expander ball and case neck, and as the neck gets bigger, it gets pulled to one side. This cannot be seen with the naked eye, but can be measured at the case mouth as 0.002" run out with a concentricity gauge. This eccentricity causes the center of gravity of the bullet to enter the chamber off center [ the bent ammo is chambered with random rotational orientation] and flings the bullet in random directions upon bullet escapement from the muzzle. According to ABBATIELLO and the NRA, this error can be up to 2moa before being limited by the chamber bending the cartridge straight.

This does not have to happen, and there are different ways around it:
1) Never use any expander ball [or any lube inside the case neck] again for any reason for the rest of your life.
2) Expand and size in separate steps
..a) Decap the used primer with a decapping die
..b) Size the brass without the decapping stem that has the expander ball.
..c) Put the decapping stem and expander ball back in the sizer die and expand on the push stroke. Only insert the case into the die far enough to engage the expander ball through the neck, but not far enough for the case neck to engage the die neck. If you must expand, a Lyman M die also works, but even flat based bullets usually do not need the neck to be expanded.
3) Use a sizer die that does not make the case neck tiny. A Redding "S" die with maximum usable size bushing will not make the neck too small. The expander ball should then pull through the neck with no deformation or some elastic deformation and no plastic deformation. Bart Bobbitt, the Camp Perry competitor that can write so well about how he does it, uses RCBS sizer dies with the necks honed out. I use Forster dies that Forster hones out to my specifications for $10 + shipping.
4) Use a Lee Collet neck die. This is THE champion of concentricity and not making brass grow to trim length. This die may look cheap to you sitting next to a Redding "S" die. But load ammo with both, shoot groups, and your view may change.

August 5, 2010, 07:52 PM
Agree wholeheartedly with Clark's assessment of the damage an expander ball can do to straight necks. My method involves a lot of separate operations, but does result in straight necks with exactly the amount of neck tension desired.

The first step is removing the spent primer using a Lyman Universal Decapping Die. Then, I use my Redding body die to bring the body back into spec and bump the shoulder back the amount I desire. The third step involves using my Redding Competition necksizing die with the size of bushing that gives me the amount of neck tension I want. If I have a "dinged" neck, I use a tapered knife sharpening tool to open up the neck and make it completely round again, prior to using the necksizing die. So, I have essentially used 3 dies doing 3 distinct operations to FL size my brass, BUT my brass is as true as I can possibly make it.


August 5, 2010, 08:17 PM
Do you anneal your case necks? If not, have you noticed any variations in neck tension as your case necks work harden after X number of firings?

I basically prep my brass the same way as Don but I neck size first, then bump the shoulder back and then trim the cases to the proper length. I only use Redding Competition dies and haven't used an expander ... ever. I use a Craftsman 1/8 punch to round the neck of any dinged cases. It works really well on new/fired brass. I will admit that I'm now sorting bullets by weight and then by base to ogive and I will be measuring neck runout and outside neck turning any cases that are out of spec. I have 400 Lapua .308 Win cases to sort so it'll take a while.


August 5, 2010, 09:16 PM
Put the knife sharpening tool and the 1/8" punch down and back away! :cool:

Get a Sinclair expander die body ( and the right size mandrel ( to fix case mouths. :D

I made the bottom Mandrel.

August 5, 2010, 09:19 PM
Put the knife sharpening tool and the 1/8" punch down and back away!

Dammit ... I was going to invent one of those and retire early!! :cuss: I suppose I'll be adding one or two to my next Midway Sinclair order.


August 5, 2010, 09:52 PM
They are perfect for getting the neck to fit your neck turning mandrel just right.

August 5, 2010, 09:54 PM
Now you're talking .... a tool that has more than one function ... it's a done deal. :D

August 6, 2010, 12:26 PM

I've got one of those Sinclair mandrels, but the knife sharpener is fast and easy.


I've got so much brass, that I doubt that I will ever need to anneal any necks. I have noticed on a few cases that the neck tension is not really there anymore, and I have been just setting them aside for fouling shots and using the next smaller sized bushing on them for now. I have often wondered whether you are likely to get the best results from body sizing then neck sizing or neck sizing then body sizing as you do. Probably doesn't amount to a hill of beans one way or the other, but if I knew somebody with a highly scientific and technical background ;), I would recommend just such a study.


August 7, 2010, 08:57 AM
When I bought a Sinclair concentricity gauge for over $100, inside the box there was a note like a Chinese fortune cookie fortune that said, ~ You will probably find the expander ball to be the culprit~.

August 7, 2010, 10:44 AM

Have you considered trying one of these Redding FL sizer that uses a bushing (, or do you not want to bump the shoulder at all?

That is basically what my custom 6 PPC sizer is, a FL sizer that uses bushings. I just adjusted it to barely bump the shoulder < .001.

Of course the 6 PPC reamers used by BR smiths, chambers and dies cut with those reamers are very close in tolerance compared to a standard FL die for standard chambers. The sides get very little sizing as well when adjusted to just barely bump the shoulder.

My Niel Jones hand sizer I used with my arbor press barely touched the sides and would barely bump the shoulder (lack of leverage). It worked fine, but the sizer cut with the same reamer used in a small custom press ( was much easier and faster.

I still seated with my Niel Jones bushing type hand die and the arbor press. Very good feel that way.

August 7, 2010, 07:57 PM

I purchased the Redding Competition Die Set, so it came with a micrometer bushing neck sizing die, body die, and micrometer bullet seating die. I've gotten used to FL resizing in 3 steps, so I don't even think about it any more.


September 5, 2010, 08:02 PM

The beauty of the bushing sizing die is that you can size the necks of a case so you'll have the proper tension on the bullet and not overwork your cases. Now, if you turn the outside of the necks the only way you may size the necks and still get the correct tension on the bullet is with a bushing. If done right, measure the diameter of the neck area in your chamber. Then turn the outside of the necks so with a bullet seated the necks measure .0015" smaller than the diameter of your chamber and you'll never have to size the necks again. Unfortunately this can only be done if you have a tight chamber. The .0015" will allow the neck to expand during firing to release the bullet. As pressures subside the case will spring back to the point that the neck will hold the bullet with the same tension every time it's used. Accuracy can be amazing.

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