What the heck just happened? Why the poor runout?

[JebWV]

I just finished loading up about 40 rounds of .264 WM.
These were with cases that I had uniformed and fireformed to my rifles chamber.

After loading these, I decided to check the runout...
First one not too bad ~0.0015".
Then it went down hill. Second ~0.012"!
And it went like this, with about half of them at better than 0.003" (not necessarily stellar, but this is for hunting rounds) and others >0.010"!

I checked the concentricity of the case necks after fireforming and they all looked good.

Nothing special with the dies...I'm using RCBS two-set dies, but I've never had this kind of problem before. Some of these are so bad that I'm nervous about shooting them.

My actual reloading steps from the uniformed and fireformed cases:
Cleaned primer pockets
Brushed out necks with bore brush on a hand drill
Lubed cases with spray lube angling a little into the necks
Resized with standard RCBS on Rockchuck (I'm guessing this is where it went South).
Trimmed cases to length with RCBS 3way trimmer
Primed & powder
Seated with standard RCBS die.

All I can think is maybe I didn't have the lockring tight when I was resizing.

I've got to be doing something stupid here, so don't be afraid to tell me.

 

[BoydAllen]

How did you set your FL die? If you have some sort of comparitor, measure a fired case shoulder to head and then one of your sized ones. Tell us what the difference is.

 

[Sheldon N]

Necks are work hardening, as they work harden it takes more effort from the upstroke on your standard RCBS dies to pull the expander ball back upward through the neck. That higher effort is pulling the neck/shoulder out of alignment and creating the runout.

 

[Martin52]

Necks are work hardening, as they work harden it takes more effort from the upstroke on your standard RCBS dies to pull the expander ball back upward through the neck. That higher effort is pulling the neck/shoulder out of alignment and creating the runout.

Agree with you on that but these cases might have only been fired once - OP refers to having fireformed the cases.
Q for the OP - how many times have the cases been fired ?

 

[jerseyjoe]

What brass are you using? What is the run-out on the case neck of a sized case with no bullet seated?

What is the run-out on the case neck after the bullet is seated?

What bullets are you using? How do they fit the seater plug?

 

[Richard Coody]

first what kind of accuracy are you looking for?

here is what i have learned about the subject.

first check concentricity after sizing and after seating. find where the problem is being introduced. i expect most is at sizing but some at seating too.

i have gone through several sizing dies attempting to reduce runout. forsters works well. a honed forsters is better. whidden full length sizing die with his expander ball kit works very well and allows you control of your neck tension. Harrells will select an of the shelf die that closely matches your chamber if you send them 3 fired pieces of brass. no doubt custom dies that match your chamber are best. The bushing dies work well but when you check concentricity after sizing they will give you a false reading. All the imperfections in the case neck have been pushed to the inside.

annealing is extremely important for consistent neck tension. without consistent neck tension you will continue to have a problem with bullet seating and accuracy will suffer.

for bullet seating the forsters seating die is hard to beat. i use the wilson in line seater and a 21st century hydro press. this way i know i have.a handle.on neck tension. sorting by seating force and concentricity have done more for accuracy than anything else i have.done.

the last step in concentricity is neck turning brass. if the neck thickness varies as much as .003 to .005 then you can't possibly make your final rounds any better than that. in fact what i find is often the runnout is about.double whatever the difference is in neck thickness

 

[Shynloco]

I agree with Richard 100%. I use Redding Dies and have noted that like it or not, concentricity INCREASES TO THE BAD SIDE whether you use a straight FL Sizing Die or even an "S" Die with a Bushing. Now as Richard suggests, if you have a custom die made that matches your chamber, that INCREASE should not occur. Funny thing that I've also found a cheap LEE FL Die will help IMPROVE that runout SOMETIMES if you quarter turn the casing 4X when FL resizing. A slight improvement also occurs if you use a Body Die using the 1/4 turn method. But as long as you get to .002 or less runout, you should be good to go. But I feel your pain as I find it irritating that an expensive die doesn't function as well as a cheapy like Lee makes. Guess the bottom line is, if you are going to spend money, spend it on a Harrel or Whidden and problem solved.

Alex

 

[Sheldon N]

Agree with you on that but these cases might have only been fired once - OP refers to having fireformed the cases.

Oops, misread the original post as the runout was increasing with each firing/sizing cycle.

 

[500Stroker]

Get yourself a FL Widden bushing die and throw away the sizing button, use differant size bushings to control the desired neck tension. I believe your problem is die related.

 

[fguffey]

Resized with standard RCBS on Rockchuck (I'm guessing this is where it went South).

If you are talking about the Rock Chucker RCBS press most reloaders can recognize one but know very little about them, and then there are instructions.

If you believe the problem with run-out happened to either side of raising the ram and lowering the ram I suggest you try this: Remove the primer punch/neck sizing plug assemble first then size 10 cases. After sizing the cases without expanding the neck measure run out. If the case body, shoulder and neck are straight the problem is not the press and the problem is not the sizing die.

After checking the cases for run out without expanding the neck install the primer punch/expander ball assemble and then size the cases and expand the neck when the ram is lowered. After expanding the neck check for run out. It is easy to form bad habits when getting information from reloading forums..

many reloaders leave the assemble loose, others use an 'O' ring for centering? I prefer to have the expander at the top to reduce the time between lowering the case and the plug being pulled through the neck. and then there are those that believe the plug pulls the neck out of shape and increases the length of the case between the shoulder and case head. And then there is the amount of effort required to lower the ram when the case is work hardened.

I have said it is possible to determine if the sizer ball increases the length of the case from the shoulder to the case head when the ram is lowered, the one thing I have not found is a reloader that can figure a way to measure the length of the case when determining what if it is possible.

I have three Rock Chuckers.

F. Guffey

 

[fguffey]

I would suggest annealing the necks if lowering the ram indicates resistance to pulling the sizer ball through the neck. And then there is bullet hold, I am the fan of all the bullet hold I can get but if the reloader is fussy about run out reduce the diameter of the sizing plug. Reducing the diameter of the sizing plug will reduce bullet hold.

And then reloaders should sign up for a short course on bullet release.

F. Guffey

 

[jerseyjoe]

I would suggest annealing the necks if lowering the ram indicates resistance to pulling the sizer ball through the neck. And then there is bullet hold, I am the fan of all the bullet hold I can get but if the reloader is fussy about run out reduce the diameter of the sizing plug. Reducing the diameter of the sizing plug will reduce bullet hold.

And then reloaders should sign up for a short course on bullet release.

F. Guffey

No, it will increase the"bullet hold" by virtue of making the bore in the case smaller, aka more press fit / interference fit.

Speaking of signing up for a short course.......

 

[243winxb]

If the different in fired neck diameter vs loaded round neck diameter is more than .008" Over working the brass is the problem.

Size a brass neck without the expander, how much smaller is the neck diameter when compared to a loaded round.

Over working the brass ??

 

[M-61]

From JebWV:
"Brushed out necks with bore brush on a hand drill".

I am not a fan of spotlessly clean necks. In fact maybe your spinning bore brush (is it metal?) leaves scratches on the inside of the clean neck and they would be scratches really going in the wrong direction. If the expander ball in the die is rough then the combination of the two could yank a neck sideways.
Just a thought.

And then reloaders should sign up for a short course on bullet release.

Never heard of this course....short or long. Where would one sign up?

 

[Richard Coody]

If the different in fired neck diameter vs loaded round neck diameter is more than .008" Over working the brass is the problem.

Size a brass neck without the expander, how much smaller is the neck diameter when compared to a loaded round.

Over working the brass ??

overworking the brass?

now why is this a problem?

 

[Richard Coody]

If you are talking about the Rock Chucker RCBS press most reloaders can recognize one but know very little about them, and then there are instructions.

If you believe the problem with run-out happened to either side of raising the ram and lowering the ram I suggest you try this: Remove the primer punch/neck sizing plug assemble first then size 10 cases. After sizing the cases without expanding the neck measure run out. If the case body, shoulder and neck are straight the problem is not the press and the problem is not the sizing die.

After checking the cases for run out without expanding the neck install the primer punch/expander ball assemble and then size the cases and expand the neck when the ram is lowered. After expanding the neck check for run out. It is easy to form bad habits when getting information from reloading forums..

many reloaders leave the assemble loose, others use an 'O' ring for centering? I prefer to have the expander at the top to reduce the time between lowering the case and the plug being pulled through the neck. and then there are those that believe the plug pulls the neck out of shape and increases the length of the case between the shoulder and case head. And then there is the amount of effort required to lower the ram when the case is work hardened.

I have said it is possible to determine if the sizer ball increases the length of the case from the shoulder to the case head when the ram is lowered, the one thing I have not found is a reloader that can figure a way to measure the length of the case when determining what if it is possible.

I have three Rock Chuckers.

F. Guffey

i have a 40+ year old rockchucker that works just fine. of course i prefer my co-ax these days.

as far as the press being the problem. i doubt it seriously unless there is an awful lot of wear on the linkage.

the sizing die? i have a cabinet full of RCBS dies. most are 30 or 40 years old. i don't buy them any more. much better options out there.

so guffey what to do if you do find that runout has been induced with the expander ball removed?

as far as sizing with the expander ball removed and then installing it and expanding the neck i have had issues. Normally the expander ball goes through the fired neck before any sizing. Then it is pulled out through the neck after sizing expanding it. if you try to force the expander ball down through the sized case often it will not fit. i have even collapsed shoulders trying. An expander mandrel is best for this situation.

the rest of your post is your typical riddles not deserving of a.reply

 

[243winxb]

overworking the brass?

now why is this a problem?

http://www.redding-reloading.com/tech-line-a-tips-faqs

 

[Richard Coody]

http://www.redding-reloading.com/tech-line-a-tips-faqs

so you send a link to a sales pitch for redding bushing dies?

what do you think happens when you overwork the neck brass? please elaborate.

work hardening? that is why we anneal.

i never have cracked necks. my brass always dies from loose primer pockets.

do i believe overworking brass is a good thing? no

that is why i recommend honed forster dies, whidden and harrel dies and the best in my collection custom dies made from my fired brass.

 

[Someoldguy]

Never heard of this course....short or long. Where would one sign up?

I'm pretty sure Guffey could get a Doctorate and the ability to speak in concise terms would still elude him.

 

[243winxb]

This happens when brass is over worked and not annealed, when using standard dies.