expander buttons -- bad?

[HomeSlice]

Hello. I've been hanging out here for several years, but don't post much - so please go easy on the new guy

I've had several people tell me that when I use the expander button on my sizing dies, I'm creating avoidable runout problems for myself. Is this true? If so, is it conceptual, or measurable?

I use Redding competition bushing sizing dies, with the bushing usually 0.002-0.003" under. I'm loading 308 for F/TR and 223 (+soon a 6 fat rat) for across the course. I'm not very good at either of those...

Any advice?

 

[BRU15]

It's certainly possible. I removed all of the buttons from my resizing dies and moved over to using an expander mandrel that gives me .002-.003 of neck tension depending on the caliber. I have found that I get far more consistent results than I ever did with the expander button. Every bullet that I seat feels exactly the same and using the Forster Ultramicrometer seating dies each one comes out with less than .001" of runout.

Are you having accuracy / neck tension (bullet hold) / SD/ES problems? If not, I'd say you're probably doing just fine and there's no reason to search for an answer to a problem you don't have.

 

[Ned Ludd]

I start out on virgin brass with Sinclair's Gen II die and oversized expander mandrel for .223 Rem and .308 Win F-TR loads. The idea is to open up all the necks to a minimum diameter that is greater than that to which the subsequent bushing will size them back down. After the expander mandrel, I size them back down using the sizing die from a Redding Type S Match die set, with a bushing appropriate to give approximately .002" neck tension (as measured by neck diameter before/after bullet seating. In theory, you could also do it the opposite way. That is, resize first with a slightly undersized bushing, then open the necks up with the appropriately sized mandrel to give you about .002" neck tension.

The purpose behind this approach is that straight out of the box, there can be significant variance in neck diameter on virgin brass (i.e some necks would be sized down significantly, some very little, if at all). Using the expander mandrel first allows the bushing die to do a more uniform job. Resizing virgin brass with the FL die doesn't push the shoulder back or size the body at all; it only sizes down the outside end (~80%) of the neck. I have been very satisfied with the performance of this approach. It is simple and straightforward and does not require the use of an expander ball. I typically get runout of less than .001"-.0015".

 

[HomeSlice]

I'll go do some reading on using expander mandrels -- i don't know much about them. I also should look into an inexpensive method for measuring runout, as I don't have a way today. I don't think my reloads are my limiting factor right now, but rather my shooting ability. While I'm not able to break into the single digit SDs, I can usually get it down to the low double digits (12-15).

Do you think it matters if I use the carbide expander or the regular steel? By what mechanism can/does the expander cause problems?

Thanks for your help.

 

[watercam]

OR you can use the bushing dies as designed and set your neck tension using the appropriately sized bushing. It seems the above use of expander mandrels would be working the brass more than necessary. Remove the expander ball from the stem. Measure the diameter of a loaded round, choose the bushing size that gives you the neck tension you desire and size one time only.

 

[BoydAllen]

There is a place for the use of expanders with bushing FL dies. If you are not turning necks, and you carefully select your bushing size so that the expander can hardly be felt at all as the sized neck is expanded, you will not create runout problems, and the IDs of your necks and their roundness will be better than they would be if you removed the expander and used a slightly larger bushing. The trick is to get the match right so that the expander is not doing much....just a little. There is also the matter of lubrication of the insides of necks before sizing, which may need to be removed after, depending on the type used. The main reason that expanders have gotten a bad rap is that the neck IDs of one piece dies are so small that when expanders are pulled through the over sized necks that the pull on the case causes case shoulders to yield slightly in an asymmetrical fashion which cocks the case necks. It has been my experience that if one has to work with these type of dies that substituting the careful use of a expander die and mandrel for the dies expander. Of course lubing the insides of necks is still required, and careful attention to how fast, the expander is inserted into the case neck so that the amount of axial force on the case is kept to a minimum. For those that want to experiment with neck tension, Whidden offers expanders (that also fit Redding dies) in different sizes. Years ago, a successful 1,000 yard shooter that I knew once told me that the last step that he used in sizing cases (which were of course neck turned) was to expand the necks with a mandrel chosen from a set that he had had made with size increments of eight a half or full thousandth. I forget which it was, but the point is that he was of the opinion that he got more consistent results by finishing his process with a slight expanding up of his case necks. I have several concentricity gauges, and use them regularly to evaluate dies. I also have one that does a very good job of straightening loaded ammo, BUT my belief is that their proper use is to diagnose equipment and procedure problems rather than fix crooked ammunition.

 

[bsekf]

I was gong to suggest a collet die but you have already bitten the bullet and have a bushing die. As usual Boyd has hit the nail with my head. Just fool with the expander and the bushing till you get the right "feel"... remember the lube!

Bill

 

[msinc]

I've had several people tell me that when I use the expander button on my sizing dies, I'm creating avoidable runout problems for myself. Is this true? If so, is it conceptual, or measurable?

Any advice?

You could be, if there is a problem with the stem or die. So yes, it could be true, but not necessarily. It is absolutely measurable if you have a concentricity gauge of some kind. Without a gauge you are guessing.

Once you get a gauge so you can check for it, take out the stem and expander ball and resize a case. At this point you cannot load this case because the neck will be sized down, but it should show zero runout on the gauge. If with no stem/expander assembly you have runout then you have a bad die. Send it back for a replacement. If the case shows zero runout, as it should, reinstall the expander assembly and size a case. If you are now showing runout try loosening the expander assembly locknut, size a case and when you retract stop when the neck is on the expander and tighten the locknut. Resize another case and check it. If the expander just needed to be centered than this should do it. If not then you probably have runout {it's bent} in the stem itself. Try a new one.

 

[alb]

You could be, if there is a problem with the stem or die. So yes, it could be true, but not necessarily. It is absolutely measurable if you have a concentricity gauge of some kind. Without a gauge you are guessing.

This; exactly this.

 

[dkhunt14]

I believe if you don't turn cases the bullet is not in centerline of the case. If you just size and don't expand the thicker part of the neck just gets pushed faster in and makes the case inside diameter uneven. Matt

 

[CharlieNC]

I like the Lee collet neck die for the final sizing, it squeezes the neck from the outside onto a mandrel so the resulting id is fixed. Also nice that it does not require any lube.

 

[BoydAllen]

In my earlier post I was just addressing the use of expanders, but since others have brought it up, I am a big fan of first using a collet die and then a properly set up body die, or the equivalent, a FL bushing die without its bushing, which amounts to the same thing. I believe that for unturned necks, and even for turned when used in chambers that have generous neck clearance that this method is the best available. Just remember that to vary the neck tension when using a collet die, you will need different sized mandrels, which are available for reasonable cost from Lee, or you can simply sand down the one that comes with the die.

 

[Thisguy65]

For the guys that are using the expander mandrels and bushing dies are you using a bushing 0.001 smaller than the mandrel size to ensure the mandrel works the brass correctly?

 

[dsbw]

Agree, LEE collet die simply the best solution.

 

[gotcha]

In my earlier post I was just addressing the use of expanders, but since others have brought it up, I am a big fan of first using a collet die and then a properly set up body die, or the equivalent, a FL bushing die without its bushing, which amounts to the same thing. I believe that for unturned necks, and even for turned when used in chambers that have generous neck clearance that this method is the best available. Just remember that to vary the neck tension when using a collet die, you will need different sized mandrels, which are available for reasonable cost from Lee, or you can simply sand down the one that comes with the die.

Like Boyd I use both methods. Collet die then body die on 6 BR, a Forster F/L die with neck opened .001" smaller than expander button diameter for 6.5X47L. I prefer the Forster dies because the expander ball is mounted high on the stem and can be adjusted to a few thou. below the neck/shoulder junction. ....... Either method yields low run out. One requires two dies and two steps the other only one die and one step. Get yourself a run out gauge 1st then decide on your preferred method. I should add that next you'll need to get into annealing to control the dynamics of case neck work hardening. .... Up grading equipment NEVER ends

 

[msinc]

.... Up grading equipment NEVER ends

aint that the fun part!!!!!

 

[HomeSlice]

Thanks for all of the help. Is there an inexpensive and/or easy to use concentricity gauge that you would recommend?

 

[SheepDog]

With a couple of "V" blocks and a dial indicator you can measure the run out of your case before seating the bullet and after. If you chamfer the inside of the neck the bullet should seat with little effort but if it is not chamfered enough it can push the neck and shoulder down and cause run out. The neck expander is unlikely to cause run out in the sizing of the case because the case "floats" in the shell holder and allows the sizing button to pull straight. As has been stated lubrication is important on the inside of the neck - a dry graphite lube it the easiest to deal with and if you use an oil based lube you will need to clean it off before you continue reloading.

 

[BoydAllen]

With enough difference between the sized neck's ID before the expander is pulled through, and the OD of the expander button, even with lubrication, necks are very likely to get significantly crooked (lots of experience with this)The trick is to minimize the difference between the die or bushing ID and the button's OD, which is a lot easier to do with bushings, or just go around the whole issue by using a two step sizing procedure as was described above.

 

[ronemus]

The type of expander can also have a bearing on runout. I favor Hornady's elliptical expanders because they're gentler - the transition is gradual rather than the abrupt change of a short button. I also use custom dies (Hornady is very reasonably priced) that size the neck slightly, and expanders that then open the neck (usually only 0.001-2"). I like a standard die rather than a bushing die because the floating bushing can create runout, especially if you size more than ~0.003-4" in one step; that's great for benchrest, but not for a SAAMI chamber. Even though I have tight chambers (~0.004" clearance) I still prefer a custom one-piece die.