Not what I expected....UPDATE

[mdesign]

...So I bought a bushing die with the right size bushings with the plan experiment with neck tension to see if I could wring a little more out of my 300wsm. I turn my necks and had been FL sizing with about .0015 for neck tension. This combination always yields a total run-out of less than a .001

So I start with the bushing die, check run-out on fired case, about .0005, resize case and check run-out again,.0000, I'm thinking this is going to be good. I seat the bullet and check the run-out and it is .002

Nothing I do changes anything, its always .002 of run-out after I seat the bullet. I can take the same case and FL size it and and seat the same bullet and get zero run-out or very close to it. The only thing I can think of is that some how the way a bushing die does not size to the neck/shoulder junction is somehow messing it up but that's just a guess.

Am I missing something?

 

[Victor N TN]

Re: Not what I expected....

I know that you probably do this. But are you cleaning the INSIDE of the case necks good? A little burned on carbon will throw it off.

If all else fails, call the bushing / die maker and pose the question to them. I currently have 5 Redding / Hornady bushing type dies. None of them have this problem.

Good luck.

 

[Austan]

Re: Not what I expected....

Is it possible that the seater isn't perfectly round, seating at a bit of an angle causing more runout?

 

[mdesign]

Re: Not what I expected....

I clean the ID of my necks with 0000 steel wool on an old bore brush and they look good to me. Both my FL and bushing die is made by Redding as is the seater so I'm not sure what to think.

Thought I'd call them on Monday and see if they had any insights to offer. Stumps me...

 

[ChrisGarrett]

Re: Not what I expected....

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: mdesign</div><div class="ubbcode-body">...So I bought a bushing die with the right size bushings with the plan experiment with neck tension to see if I could wring a little more out of my 300wsm. I turn my necks and had been FL sizing with about .0015 for neck tension. This combination always yields a total run-out of less than a .001

So I start with the bushing die, check run-out on fired case, about .0005, resize case and check run-out again,.0000, I'm thinking this is going to be good. I seat the bullet and check the run-out and it is .002

Nothing I do changes anything, its always .002 of run-out after I seat the bullet. I can take the same case and FL size it and and seat the same bullet and get zero run-out or very close to it. The only thing I can think of is that some how the way a bushing die does not size to the neck/shoulder junction is somehow messing it up but that's just a guess.

Am I missing something? </div></div>

Couple of things. Are you cranking down the bushing with the die stem, where it's not floating? I let my busings float and self-center themselves, but this means that I'm not quite sizing the neck all the way down to the neck/shoulder junction.

I don't have a concentricity gage to measure, but either try floating the bushing if you're not, or not floating it if you are.

Scondly, could the bushing be drilled off center, or its inner diameter be out of round slightly?

It would be nice if you had another buying to use instead of the one you're currently using.

Chris

 

[1GoodEye]

Re: Not what I expected....

I read an article on load work up at one time (I think on 6mmbr.com on Darrel Hollands 6.5 x 47) about turning the neck bushing upside down to change the neck tension just a scocsh with the redding bushings. I don't know that this will change the run-out on your loaded round, but I would be interested to see if it changed anything with your problem (may not have the tension you are looking for but it may help identify the issue). Seems that the bushing is the only variable in the equation. Might be worth a try.

Have you check run out at a couple of places on the plane of the case? Depending on where the run-out starts, this could also point you in the right direction wether it is in the die or the bushing.

Just my $.02

1GE

 

[308isgreat]

Re: Not what I expected....

Are you using a different seater die with the neck sizing die?

Are you using the same bullets with this die? The same lot # on the bullets?

Also, are you checking for runout on the same part of the neck with both the FL and neck dies?


Very interesting situation, I hope you figure it out!

 

[mdesign]

Re: Not what I expected....

Chris - running my bushing 1/2 turn loose and get the same r/o with either a .334 or .335 bushing. That all the bushings I have for now, the .336 & .337 are on back order from Midway. The .335 gives me .0015 neck tension duplicating my FL die.

Same lot of bullets, in fact it is the same case and bullet tested both ways. Puzzling...

 

[Enios]

Re: Not what I expected....

My younger brother has noticed the same thing when he neck sizes with his Forster bump bushing neck sizer...put the case in your calipers and slowly turn it and see if it's higher at some point. We've noticed the necks aren't square when he uses his on a 300WSM. My 308 & 243 doesn't give me that problem but I bought the Micro adjustable Redding for them and don't use an expander with them. I do however full length size with a Redding body die to bump the shoulder back .001 to .002 each loading.

 

[Winchester 69]

Re: Not what I expected....

There is a misalignment in the fired case that's not being corrected by the neck die. After the bullet is seated, the run-out measurement is amplified. As Enios observed, a die that captures the case like the Competition Redding neck die and FL dies corrects the neck misalignment. Experimenting with your measurement process may detect this misalignment.

 

[Austan]

Re: Not what I expected....

I might have read this wrong but I thought the OP was using a FL die with bushings to change neck tension, not a neck sizing die. He wrote that after sizing the run-out is zero and after seating a bullet there is run-out. Why then would the problem be in the sizer and not the seater?

In a cheap lee seating die I had a lot of run-out. I chucked a bullet in my drill with some 220 compound and ran it a while. Then repeated with a fresh bullet and 320 then 600 and it reduced the run-out considerably. I'm guessing there was some type of burr in there causing the problem. This also helped to eliminate the ring left on the bullets while seating. I did this as more of an experiment than anything but it worked. If it were a comp seater and I had that much invested in it, it would go back for replacement.

 

[1GoodEye]

Re: Not what I expected....

Bump

Curious what was found out here.

1GE

 

[mdesign]

Re: Not what I expected....

Spoke with the tech staff at Redding and it turns out this is not the first time they heard of this..

First of all, I need to clarify that the bushing sizer die I bought was a FL bushing die. Second, I am very frugal by nature so my every day brass has a million miles on it.

...now back to the problem at hand. Further investigation showed be that the sized case neck had less runout in it than the bullet that was seated into it making me question if my neck tension was indeed what I thought it was or if the run out was partially caused by the bullet not being held tightly (as in poor contact) by the ID of the neck.

The first thing Redding said to try was a smaller ID bushing so that the sizer button would straighten the neck from the ID as it pulled back through. The neck wall was thin enough that the expander slipped through with very minimal contact when using a .335 bushing. Changing to a .333 bushing undersized the neck just enough so that the expander could apply more force to straighten the ID of the neck as it came back through. Using the .333 bushing resized the neck less that my FL die. Using this method the runout using the FL bushing die is about .001 or a little less.

The other thing they said is that bushing dies are usually very picky about consistency in neck wall thickness and that cases with a million miles were not good because the necks stretch thinner going forward as they are fired. I checked a few cases and found that the wall thickness was about .0004 thinner than back closer to the shoulder.

In the end, they recommend that you run a little smaller bushing so that the button helps to straighten the ID of the neck. In theory you can size with a bushing that makes the neck tension you want and not use a expander but if everything else is not just right you will most likely have runout issues.

I tried the .335 bushing with some new brass and got very good runout. Redding strongly recommended high quality brass for better results. They said that issues like I experienced are becoming very common but the less than SAMMI brass that is being mfg today.

Kind of long but that's what I learned

 

[sawgunner2001]

Re: Not what I expected....

And here we've been pulling off our expander balls all this time because they cause run-out. And now Redding is telling us to put them back on. And in your experience the expander ball <span style="font-style: italic">reduced</span> run-out?

I'm truly mystified.

 

[mdesign]

Re: Not what I expected....

Yes, in my case it did reduce runout. I think the variable is the quality of the brass. They did not speak well of WW brass or any US maker of brass but I will say that testing with fresh Lapua and WW brass yielded the same accuracy from my rifles so I shoot WW because it is cheaper and lasts a long.

Evidently they have also learned (or are admitting) that bushing dies are not always better as they talked of some of the inheriant isses related to machine tolerances when making a sizing die that uses a bushing.

They have told me more than once that unless every thing is close to perfect and standard FL die will give less run-out on the average because the "chamber" is cut with a single operation as opposed to the bushing die requireing a tool change and two setups.

They said that unless the brass is very concentric, it is usually a better strategy to go with a slightly smaller bushing and use the expander a little to help straighten the ID. They said this method does work the brass a few thou more than a larger bushing but does not work it nearly as much as the small neck in the standard FL sizing die.

I plug gauged the neck in my standand FL die and it measured .3305 while a fired case measures .342. Quite a bit of reduction....

In the end the reloading manufactures almost always fault the brass and I think they are mostly right. Redding provided a much better technical discussion than some of the others i have spoken to.

 

[DocB]

Re: Not what I expected....

mdesign,

Thanks for passing along Reddings current thoughts about how to use their dies.

Have fun,
DocB

 

[former naval person]

Re: Not what I expected....

Try lubing the inside of the case neck after cleaning with some lock ease on a Q-Tip....the dry graphite seems to help reduce the runout upon seating. ALSO...the fact that you are checking the outsides of the necks...could be that the inside isn't concentric with the outside. Have you checked neck wall thickness to see that they are consistant?

 

[308sako]

Re: Not what I expected....

Deleted in protest!!