Sizing Dies, Expanders, and Concentricity

[JohnW...ski]

Sometimes ignorance is bliss. I just got a 21 st Century Concentricity Guage and happened to check some loaded .223 ammo I have, I might add I made High Master using this ammo last year, so it can't be too bad, however the runout of the bullet at the area where the ogive would meet the rifling is about .005 in some cases more. I checked the runout at the neck of some sized but unloaded cases and it is running out .003 to .005. Next I checked some fired cases and found zero runout in most cases, some cases had just a hint of indicator movement, I have no problem with that. I then removed the decapping assembly from my sizing die and full length sized a few cases, again little to no runout. I installed the decapping asssembly and sized a few cases, the runout was .003 to .005. I installed a new decappping assembly and now get runout of close to .001 occasionally but not often up to .002. So, I feel I have made some progress but can do better.

A Redding "S" die with carbide expander has been ordered, I am hoping to improve on what I have already gained. I also recall reading here that some of you size and expand seperately. I would like to know more about that. Is the decapping assembly simply removed and then used later as a seperate step? What about decapping? Or, are seperate and differant tools being used for each step?

All this probably isn't necessary when shooting across the course but I also have set up a
6mm AR from Robert Whitley, it is serving two purposes, I wanted to see how the accuracy compares with my .223 match rifle, which is why I didn't just build a bench rest rifle, and I wanted to use it this year at the local 200 yard egg shoots. Anyway the rifle has a 24" heavy barrel and I am using a 32X Bushnell 4200 scope. My intent is to get the 6 mm setup to be much more accurate than the .223 which it is to a point. I am also willing to take some extra steps to get better accuracy with the 6 mm. With the amount of shooting I do across the course that isn't as practical and as I have noted, even necessary.

Thanks,

John

 

[vern]

Ill offer up a couple of things.

Runout depends on who is typing or who's book your reading.
For example Boyer says that runout in the amounts you describe shoot fine for him, on the other hand Ratigan says basically if it doesnt go in straight it will not straighten itself.

On my setup my dies do not alter my cases when they are fired in my chamber they have less than .001 after the dies they are the same.
I annealed some last year for giggles. After annealing they were .008-.012 out. After sizing no change. After firing once in my chamber back to less than .001.

Most of us shoot with dies that have bushings and no expanders. BR shooters that is.

 

[flinginammo]

john,
i just watched the video in your sig. I thought it was unfinished to say the least. To finish it up, my wife should have been on there because she uses the video game and ketchup idea also. She tells our kids if they dont sit down she is going to beat them down with a bottel of ketchup! And will also shove that video game up there rear if they dont put it down while at the table. Duct tape is also one of her tactics. Any way, I believe her way works better,, thanks
PS- i have nothing knowledgable to add on your question. i am just bored

 

[BoydAllen]

The problem with expander balls comes when the neck ID of the die that they are in is too small. Years back, a fellow that I know, that is a High Master in Service Rifle (M1A) told me that he measured the necks of a lot of LC that he planned to use and ordered a custom small base die from RCBS, one that had the ID of the neck custom reamed to his brass. If the die is not too small, and you are using unturned brass that fits so that the expander only has a couple of thousandths of "work" to do, coming back through the neck, then you will have the same runout as brass sized without the expander, but you can't fix the die with a carbide expander ball. You need a proper die. IF you want to test this, get an extra expander ball, and abrade it down till the working relationship that I have described is established. a couple of thousandths difference between sized with and sized without. Make sure that you polish it. This brass will require fixing before loading, because the neck IDs will be too small, but it will, I think be worth the effort. Start by measuring the OD of a neck sized without the expander and then with, that will tell you something about the difference that you already have. Then, if you want take a little of the expander and do the test again, and so on. I think that you will find the results interesting.

 

[JohnW...ski]

Ill offer up a couple of things.

Runout depends on who is typing or who's book your reading.
For example Boyer says that runout in the amounts you describe shoot fine for him, on the other hand Ratigan says basically if it doesnt go in straight it will not straighten itself.

On my setup my dies do not alter my cases when they are fired in my chamber they have less than .001 after the dies they are the same.
I annealed some last year for giggles. After annealing they were .008-.012 out. After sizing no change. After firing once in my chamber back to less than .001.

Most of us shoot with dies that have bushings and no expanders. BR shooters that is.

So, am I correct in thinking the expander is re-installed in the die and then just the expander is run through the mouth of the case?

 

[Turbulent Turtle]

Well, the way I do it is I remove the expander ball from my Redding S-type bushing die and use the plastic grommet instead. Next, I insert the appropriate bushing that will give my brass an OD that is about .002 smaller than the OD of the same brass with a bullet inserted. Then I just size my brass, decapping at the same time, tumble, prime, load and set the bullet.

If I am going to the trouble of controlling the neck tension of my rass, the last thing I need is some expander ball to ruin it for me. Also, Expander balls have the nasty habit of stretching cases.

I have a bushing each for Lapua, Winchester and LC in .223. IIRC, the one for Lapua is the largest (because that brass is thickest), followed by the one for Winchester, which I think was just .001 or 2 smaller and then the one for LC was about .005 smaller (thinner brass.) If you need the exact diameters, let me know and I will go look at my equipment.

 

[BoydAllen]

If you pick a bushing that only has the expander 1-2 thousandths of work, it will not ruin the brass. Evidently a lot of shooters have not done the comparison of a case sized with the expander and without, using a typical one piece die, and have therefore concluded that all expanders are somehow inherently evil. If anything, it is the size of the hole that the neck is sized by that causes the problem. With a bushing die, This can be controlled so that it is not a problem, and by using the correct bushing in conjunction with the expander, on unturned brass, the neck tension will be more uniform, and the ID of the neck will be rounder, because the irregularities in thickness will be pushed to the outside. With turned necks, the expander is not needed or desirable.

 

[JohnW...ski]

So if I use the right bushing I can size and decap and I will be done. No extra steps, sounds easy.

Thanks,

John

If you pick a bushing that only has the expander 1-2 thousandths of work, it will not ruin the brass. Evidently a lot of shooters have not done the comparison of a case sized with the expander and without, using a typical one piece die, and have therefore concluded that all expanders are somehow inherently evil. If anything, it is the size of the hole that the neck is sized by that causes the problem. With a bushing die, This can be controlled so that it is not a problem, and by using the correct bushing in conjunction with the expander, on unturned brass, the neck tension will be more uniform, and the ID of the neck will be rounder, because the irregularities in thickness will be pushed to the outside. With turned necks, the expander is not needed or desirable.

 

[BoydAllen]

Yep,
Just don't forget to watch your shoulder bump. Don't do it by feel. Measure.

 

[Martin52]

One further option is to order a die from Forster who will hone the neck portion (make it slightly wider than standard) so as to not reduce the neck diameter excessively when re-sizing. When the ram is raised, the expander ball just kisses the inside of the case neck. I get run out of about 0.001 this way.

martin

 

[markm87]

Most of us shoot with dies that have bushings and no expanders. BR shooters that is.

This! I'm not a BR shooter, but I figured out the expander had to go years ago.

 

[Keith Glasscock]

One further option is to order a die from Forster who will hone the neck portion (make it slightly wider than standard) so as to not reduce the neck diameter excessively when re-sizing. When the ram is raised, the expander ball just kisses the inside of the case neck. I get run out of about 0.001 this way.

martin

My neckturned brass works the same way. The sizing die only sizes .001 smaller than desired. I get runout readings in the vicinity of .001 or less for my sized brass.

Neck expander balls are not the problem oversizing the case neck and trying to correct that oversizing is.

Keith