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What the heck just happened? Why the poor runout?

After my recent post about inconsistent runout, a friend and I figured out the reason for my excessive RO. The rounds that had a large RO were because I wasn’t lubing the shoulders enough when bumping. This was causing the shoulders/necks to be cocked even in a custom full length body & neck die. Because I was under lubing, this was giving me some rounds with a RO up to .008. Went back thru all my loaded rounds and my prepared brass and resized all. Also, the batch of loaded ammo that had excessive RO was all re-bumped using a bump die with 2X the amount of lube. The runout returned to .0005-.00015. Today, I shot at 500 yds shooting numerous 5 shots groups. Shooting the .008 RO rounds, most of the groups were approximately 20-30% larger. Going forward, if the RO of my loaded rounds are more than .002, they are going to be used as “foulers” only. Because of this process, all this brass is going to be re-annealed before using.
Bottom line, don’t skimp on the lube.
Ben
 
After my recent post about inconsistent runout, a friend and I figured out the reason for my excessive RO. The rounds that had a large RO were because I wasn’t lubing the shoulders enough when bumping. This was causing the shoulders/necks to be cocked even in a custom full length body & neck die. Because I was under lubing, this was giving me some rounds with a RO up to .008. Went back thru all my loaded rounds and my prepared brass and resized all. Also, the batch of loaded ammo that had excessive RO was all re-bumped using a bump die with 2X the amount of lube. The runout returned to .0005-.00015. Today, I shot at 500 yds shooting numerous 5 shots groups. Shooting the .008 RO rounds, most of the groups were approximately 20-30% larger. Going forward, if the RO of my loaded rounds are more than .002, they are going to be used as “foulers” only. Because of this process, all this brass is going to be re-annealed before using.
Bottom line, don’t skimp on the lube.
Ben

awesome. Glad you figured it out. might start checking your bump with a comparator after sizing just as a QC check. i don't lube my shoulders though. just the case body with imperial sizing wax and imperial dry neck lube for the neck.

confirms my findings. you can see runout on paper
 
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This happens when brass is over worked and not annealed, when using standard dies

Not true, I have said many times there is something about the sequence of events that happens between pulling the trigger and the bullet leaving the barrel the reloader just does not understand.

Many years ago I made case spinners, I found it was easier/faster to spin/clean 20 cases than it was to tumble. Anyhow, spinning was a good way to separate cases.

And then there was that reloader that went to the range and fired 5 rounds before he discovered the fifth round was ejected without a neck, He then checked the first 4 cases he fired and found none of them had necks, and he wondered? How did the necks get out. Anyhow, he called me and said there was something about what he was doing that needed to be changed.

F. Guffey
 
Not true, I have said many times there is something about the sequence of events that happens between pulling the trigger and the bullet leaving the barrel the reloader just does not understand.

Many years ago I made case spinners, I found it was easier/faster to spin/clean 20 cases than it was to tumble. Anyhow, spinning was a good way to separate cases.

And then there was that reloader that went to the range and fired 5 rounds before he discovered the fifth round was ejected without a neck, He then checked the first 4 cases he fired and found none of them had necks, and he wondered? How did the necks get out. Anyhow, he called me and said there was something about what he was doing that needed to be changed.

F. Guffey

Well Mr. Guffey,
Once again you do not disappoint with your comments, as strange (and incongruous) as many find them. Perhaps if you stayed on topic, your comments would better serve the initial poster.

Alex
 
Well Mr. Guffey,
Once again you do not disappoint with your comments,

Shynloco, thank you, I do not look at reloading through little biddy eyes. I have to assume reloaders on this forum know and understand reloading, in my opinion too many of them have potty mouths and potty fingers, they offer nothing. 243 posted a picture of cases with split necks/cracked necks, he claims the cases are work hardened. I consider the possibility the cases are work hardened and are brittle. I have fired 100 rounds of new ammo. out of the 100 I have had 20 of the cases split up the side through the case body and or had split necks and or the necks separated from the shoulder.

Again, I made case spinners, for me there was no faster way to find a work hardened case than shove a case spinner into the neck of the case. There was a time I thought noting of necking a 30/06 case up to 35 Whelen when determining if the case would stretch that far before splitting.

Back to run out and when did it happen? I have no interest in selling someone a tool they do not need, I am the fan of the reloader understanding the tool he uses and owns. I am the only reloader that has pushed his way back from the keyboard to check the Rock Chucker, I have three Rock Chuckers that are not cam over presses, I am the only reloader that can turn a Rock Chucker into a cam over press and I am the only reloader that understands a cam over Rock Chucker will not work my Piggy Back 11 attachments because the attachments come with a one way clutch.

Picking up horse shoes: The smith pitched the shoes into a pile of sand for cooling.

F. Guffey
 
Not true, I have said many times there is something about the sequence of events that happens between pulling the trigger and the bullet leaving the barrel the reloader just does not understand.

I have often said that for some reloaders there is something about the sequence of events from the firing of synapses between the ears and the typing of keys on a keyboard that no one else can understand.
 
Thank you all for the good suggestions. Sorry for not replying sooner, but I’ve been shooting/working on these and I took the my kids hunting today for youth deer season…didn’t get anything.


Anyway, after investigating this, I think the following:
1. Inconsistent amount of neck lube.
2. The Winchester brass has very poor neck consistency and has manufacturing burrs around the rims causing inconsistent seating in the shell holder.
3. My shell holder is square in line with the resizing die on the upstroke, but on extraction, the shell holder is no longer square. There is no debris that I can find causing an issue, I just think it is poor tolerance on the topside of the locking flange on the Lee shell holder or the RCBS rock chucker ram.
4. The expander is not concentric with the die. I’ve polished the expander ball with 2000 grit paper, and I’m sure the mandrel flexes when used, but it is not centered with the walls of the resizing die.
5. My RCBS neck turner is probably doing more harm than good.


The fireformed brass has runout of <0.0015”.
Runout on the resized brass with without using the neck expander is the same.
Runout using the neck expander increases to 0.002” to 0.004”.
Neckturning with the RCBS neck turner, increases the runout up to 0.003” to 0.007”.
Running it back through the resizing die at this point decreases the runout back down to 0.001” to 0.003”.

The length to the shoulders on all of the loaded rounds were within +/- 0.0005”.
Firing did not change the length to the shoulders (I only partially necksized the fireformed cases).
While resizing, I’m not bumping back the shoulder, but I check to make sure they chamber without resistance.

I took a couple of the cases that will be trashed and resized over and over, while turning in the shell holder. This slightly improved concentricity, but began to lengthen the shoulder after about 4 resizings.


So to fix the issue, I figure:

I should start with a quality brass and consistently lube the necks.
Switch shell holder or true it on the lathe and if that doesn’t fix it, invest in a better press.
Replace the decapper/neck expander mandrel.
Get a better neck turning solution.
 
Anneal brass when needed. Lube inside of case necks when using dies that tend to over size(make too small) the neck and use the button to bring it back to a suitable size.
 

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