What is causing case to case runout variation??

[Texas10]

If the Lee is leaving impressions in the neck wall, it means you're applying too much pressure. Back off the die a bit. I use the Lee neck sizer and raise the ram only part way while feeling the case being sized SOME, then lower the ram, rotate the case 90 degrees and go all the way up on the ram. Run out is below .001

Nothing wrong in my way of thinking with two firings before bumping the shoulder back. It just means cases are fully fire formed. Of course, if you're shooting competitively you don't want your string interrupted by a hard to chamber round, so FL or shoulder bump every time is a good plan.

I have also had many an off center round shoot right into the group, but then I'm not shooting in competition.

Interestingly there are some posts recently referring to studies utilizing ultra short barrels and high speed photography where it is clear that the force of the primer detonation unseats the bullet before the powder charge ignition, and ramming the bullet into lands.

Now imagine a perfectly sized brass with zero neck/bullet run out but with a couple of thou. clearance between the case wall the the chamber. The round is going to set slightly cocked in the chamber and when the bullet unseats and is driven forward it may engrave just slightly off axis with the barrel.

I've read that some competition shooters will mark the high point of neck runout, and chamber the round with the mark at a specific orientation, perhaps helping to engrave the bullet more inline with the axis of the barrel.

In the final analysis, I am a firm believer that anything one does to increase confidence in ones self has more to do with success than most of these little tweaks actually do.

 

[rwj]

A neck sizing die does not support the case body in alignment with the neck.

Redding’s Competition series dies support the case during neck sizing and bullet seating operations...

 

[Uncle Ed]

Redding’s Competition series dies support the case during neck sizing and bullet seating operations...

The OP stated he was using a standard Forster neck sizing die. And the Redding Competition die is a bushing neck sizing die and the sliding sleeve that holds the case body is still bigger than the fired case.

At the Whidden custom die website they tell you they get more concentric cases with non-bushing full length dies.

 

[rwj]

The OP stated he was using a standard Forster neck sizing die. And the Redding Competition die is a bushing neck sizing die and the sliding sleeve that holds the case body is still bigger than the fired case.

The Redding sleeve contacts the case shoulder for centering, not the body. Nonetheless, I agree that a full length die will likely yield cases having less runout. I’ve found the Redding works well for my needs, especially when trying to determine the optimal neck tension by simply changing the bushing.

 

[mikecr]

For me there is nothing wrong with Redding body die shoulder bumping prior to bushing neck sizing.
However, my body dies are customized to eliminate sizing below shoulders, and I use Wilson hand dies for neck sizing & seating.
The Wilson neck sizing dies have so far been tight enough in the bodies that my bumped cases could not easily be pushed all the way in by hand (bushing removed). It's a slight squeeze.
They do not free fall out after sizing. I pop em out with a little tweaker screwdriver.

If your body die is leaving a lot of clearance in the neck die, then I would test for which to replace in the process.

 

[Uncle Ed]

The OP sized his cases first with a body die that created more body side clearance in his Forster neck sizing die. This extra wiggle room along the case body and the fact that the Forster neck sizing die doesn't contact and center the case shoulder is why he is getting more neck runout.

The OP wasn't using a Redding Competition die, a Wilson die or a bushing die. So why add more garbage and confusion to the OP posting.

The OP is getting more neck runout because his case necks are not centered and aligned with the case body in his neck sizing die. I also think the variations in the amount of neck runout are caused by neck thickness variations.

Bottom line, the OP would have been better off sizing his cases in a standard full length die without the expander, and then use a expander die to expand the necks. Or keep it simple and just use a Forster full length benchrest die with its high mounted floating expander.

 

[rwj]

The OP wasn't using a Redding Competition die, a Wilson die or a bushing die. So why add more garbage and confusion to the OP posting.

To identify options of which the OP may not be aware... one of the many benefits that this site provides...

 

[Iowa Fox]

The first thing that comes to my mind is what case lube are you using and how do you apply it?

 

[Bc'z]

The OP sized his cases first with a body die that created more body side clearance in his Forster neck sizing die. This extra wiggle room along the case body and the fact that the Forster neck sizing die doesn't contact and center the case shoulder is why he is getting more neck runout.

The OP wasn't using a Redding Competition die, a Wilson die or a bushing die. So why add more garbage and confusion to the OP posting.

The OP is getting more neck runout because his case necks are not centered and aligned with the case body in his neck sizing die. I also think the variations in the amount of neck runout are caused by neck thickness variations.

Bottom line, the OP would have been better off sizing his cases in a standard full length die without the expander, and then use a expander die to expand the necks. Or keep it simple and just use a Forster full length benchrest die with its high mounted floating expander.

Given the tools he has at hand and not spending any more$$$$, would he be better off sizing necks first before doing case body?
Just thinking out loud

 

[Uncle Ed]

Given the tools he has at hand and not spending any more$$$$, would he be better off sizing necks first before doing case body?
Just thinking out loud

The Op has stated he has a Forster full length die on the way, that in my opinion is better choice than sizing the case twice.

The main reason reloaders use a body die and a Lee collet die is because it produces less runout than a bushing die in factory chambers.

So if you are going to lube the case using a body die then just use the Forster full length die and size the case once.

And with the Forster full length and the OPs "Sinclair micrometer thingy" he will see far less neck runout.

My mind has ponder these things many of hours lol

I'm using the Sinclair micrometer thingy with the sliding rollers that you set the case on and then can measure on the neck or the bullet or whatever you like. I forget exactly what it's called. Not the highest quality tool in the world, but i dont think its the tool. Actually pretty satisfied with it and I think it was under $100 with the dial micrometer

 

[Bc'z]

Oh I get it, and have been following closely.
And I understand the remedy. But this still doesn't answer the basic question.

So given the tools at hand would "ANY" individual sizing brass in the manner that the OP was, would they be better off doing necks first body second?

The Op has stated he has a Forster full length die on the way, that in my opinion is better choice than sizing the case twice.

The main reason reloaders use a body die and a Lee collet die is because it produces less runout than a bushing die in factory chambers.

So if you are going to lube the case using a body die then just use the Forster full length die and size the case once.

And with the Forster full length and the OPs "Sinclair micrometer thingy" he will see far less neck runout.

 

[Uncle Ed]

Oh I get it, and have been following closely.
And I understand the remedy. But this still doesn't answer the basic question.

So given the tools at hand would "ANY" individual sizing brass in the manner that the OP was, would they be better off doing necks first body second?

There is nothing in a standard neck sizing die to center the case body with the case neck and keep the two concentric.

And there will be less neck runout with a standard full length die.

The cheap Lee full length die below would produce less runout than what the OP is getting using two dies. The expander collet holds and centers the expander, meaning there is very little chance the expander being locked down off center.

I tested the .223 dies below for neck runout after sizing and the neck sizing dies produced the most neck runout. And the Forster full length die produced the least amount neck runout with their floating expander.

I see absolutely no sense in sizing the case twice when the Forster full length die will produce the least runout.

Below I installed a Forster expander and spindle assembly on my Redding .243 full length die and greatly reduced neck runout.

Its amazing how reloaders will praise the Forster Co-Ax press that lets the die and case float. But then fail to understand the merits of the Forster full length dies and their floating self centering expander. The 6.5 Guys even said in the video I posted stated they got less neck runout with the Forster full length die vs the Redding full length bushing die.

 

[Uncle Ed]

270 ftw

The Redding bushing FAQ tells you if your case necks have .002 or more neck thickness variations to use the expander included with the Redding die. Meaning 99% of the time if you are not neck turning your necks you need to use a expander. And using a expander is not the end of the world as many people tell you in forums, especially if you do not want to neck turn your brass for a factory rifle.

I have had brand new Remington .223 cases with over .009 neck thickness variations. And the simple Redding neck thickness gauge below will tell you a great deal about the quality of your cases. You can use this gauge to sort your cases and not neck turn. You can also measure the neck thickness variations and subtract them from your neck runout reading for actual runout.

You can measure how much your Forster full length die reduces the neck diameter after sizing with the expander removed. And if the die reduces the neck more than needed Forster will hone the neck of their die to your desired diameter for $12.00.

And remember there is a difference between a off the shelf factory rifle that allows the case neck to expand more than a custom barrel with a tight neck chamber. You have no control over the amount the neck expands in a factory rifle. But you can control the amount the die reduces neck diameter by having Forster hone the neck of the die.

Read the link below and how much the necks are worked by the different resizing dies. And remember that Forster will hone the necks of their full length dies to your desired diameter.

Are Your Sizing Dies Overworking Your Rifle Brass?
http://www.massreloading.com/dies_overworking_brass.html

Is it the same for all manufacturers of dies?
I wondered if simply changing the brand of die would fix the problem. So I purchased several manufacturers' full-length .223 resizing dies to try out. The results are shown in Table 2.

 

[mikecr]

Our best die is our chamber. Cases pulled smoking from it are as straight as they will ever be.
Due to thickness variances and springbacks, ANY sizing done degrades this a bit, and the more of it, the worse. So the direct counter to runout is not more or FL sizing, it's as little sizing that we can do well.

You really can't claim that any off the shelf die will provide better results because you don't know how well that die will match with a local chamber/situation. Such declarations apply only with custom dies built from fully fire-formed cases, and cartridges well designed for many reload cycles, and a plan to make straight ammo.

My body dies are custom and squeeze bodies (without sizing) while bumping shoulders. My cartridges are not long for capacity, with low shoulder angles, so thickness variance does not spring back to bananas. My plan for straight ammo is reducing sizing to bumping and partial neck. If/When I hit a full thou of TIR on a case, it's raked into the shiit can as different at least.
Many existing reloading situations go/should go a different path. I don't even know what OP's cartridge is, and my inputs are provided only because he's attempting what I happen to do with better success.
Again, that's my situation.

 

[270 ftw]

270 ftw

The Redding bushing FAQ tells you if your case necks have .002 or more neck thickness variations to use the expander included with the Redding die. Meaning 99% of the time if you are not neck turning your necks you need to use a expander. And using a expander is not the end of the world as many people tell you in forums, especially if you do not want to neck turn your brass for a factory rifle.

I have had brand new Remington .223 cases with over .009 neck thickness variations. And the simple Redding neck thickness gauge below will tell you a great deal about the quality of your cases. You can use this gauge to sort your cases and not neck turn. You can also measure the neck thickness variations and subtract them from your neck runout reading for actual runout.

You can measure how much your Forster full length die reduces the neck diameter after sizing with the expander removed. And if the die reduces the neck more than needed Forster will hone the neck of their die to your desired diameter for $12.00.

And remember there is a difference between a off the shelf factory rifle that allows the case neck to expand more than a custom barrel with a tight neck chamber. You have no control over the amount the neck expands in a factory rifle. But you can control the amount the die reduces neck diameter by having Forster hone the neck of the die.

Read the link below and how much the necks are worked by the different resizing dies. And remember that Forster will hone the necks of their full length dies to your desired diameter.

Are Your Sizing Dies Overworking Your Rifle Brass?
http://www.massreloading.com/dies_overworking_brass.html

Is it the same for all manufacturers of dies?
I wondered if simply changing the brand of die would fix the problem. So I purchased several manufacturers' full-length .223 resizing dies to try out. The results are shown in Table 2.

Im all for using the expander even though neck wall thickness on norma brass is less then .002 variance. Inside consistency is more important than out outside consistency before the seating step in my opinion. Forsters interchangeable size expander ball system allows me to experiment with different neck tensions as well. As i stated before it doesnt cause any additional runout. And i do order my Forster dies honed out for minimal brass working. I only removed the expander to prove where the runout was coming from.

My question really was why do i get .001 runout on some strokes and .006 on others. If i can get one piece to come out with .001 i should be able to get them all to come out that way all other thing being equal. Even with my less then ideal set up of sizing bodies first and then necks. Is it play in the linkage of my cheap RCBS press? Is it the speed i bring the handle down or back up? Are some of the rims of the cases not perfectly square and translating to the necks entering the dye slightly off center ( rims is not a variable I can control, bolt-face might not be square to chamber and causing rims to warp slightly. Just throwing that out there, dont even know if thats possible). And the theory i will be testing tonight.........not having perfectly consistent outside chamfer(deburr). This is just my hypothesis......maybe as the lip of the case first contacts the die if its not square it starts the case in there off center. I'm going to intentionally mess up some lips and they try a batch of my very best most consistent deburring. Might not yield any results at all but im going to try. Again if some come out acceptable .001-.002 and some dont...what i what to know is whats the variable causing it.

 

[BenPerfected]

This is my go to tool to quickly measure neck thickness in multiple places. It is from Sinclair/Brownells.
Ben

 

[Uncle Ed]

My question really was why do i get .001 runout on some strokes and .006 on others. If i can get one piece to come out with .001 i should be able to get them all to come out that way all other thing being equal.

There is nothing holding and centering the case body in alignment with the case neck in your neck sizing die. And when the neck is reduced in diameter it is free to move in any direction it wants to and create neck runout.

The same thing can happen with a bushing die when reducing the neck diameter .004 or more. The sizing forces can make the floating bushing move from side to side and even tilt.

And if you did not turn the necks the variations in neck thickness can add to the runout problem.

And the added case body clearance in the neck sizing die could let the base of the case to be off center and tilt slightly.

And once you switch to a full length die the case body and case neck will be held in alignment with each other when sized.

 

[270 ftw]

There is nothing holding and centering the case body in alignment with the case neck in your neck sizing die. And when the neck is reduced in diameter it is free to move in any direction it wants to and create neck runout.

The same thing can happen with a bushing die when reducing the neck diameter .004 or more. The sizing forces can make the floating bushing move from side to side and even tilt.

And if you did not turn the necks the variations in neck thickness can add to the runout problem.

And the added case body clearance in the neck sizing die could let the base of the case to be off center and tilt slightly.

And once you switch to a full length die the case body and case neck will be held in alignment with each other when sized.

So your saying the ones that come out "good" i am just getting lucky on...i was afraid of that.

 

[Uncle Ed]

So your saying the ones that come out "good" i am just getting lucky on...i was afraid of that.

If you remove the expander from a full length die and size a case you should have very little to no neck runout.

You removed the expander from a neck sizing die and still got as much as .006 neck runout. This is because with the neck sizing die there is nothing centering the case body with the case neck. So yes you were lucky and the runout readings you got were pure chance.

When your new Forster full length die comes in size the cases with excessive neck runout again and see ig the neck runout decreases.

And again I got the most neck runout with bushing neck sizing dies and the least with the Forster full length dies.

 

[Dusty Stevens]

lets get back on track here- if your cases are straight out of the chamber but runout is induced after sizing.... its your sizing die. with off the shelf dies its a crapshoot that out of a dozen of the same model one may work. neck sizing is an exercise in futility- everytime you run a case into a die it has a chance to get worse. just get a good top quality fl bushing die and be done with it. your press isn't doing it and your shellholder isn't doing it. one call to whidden will render your concentricity gage into a dust collecting shelf ornament and you can concentrate on enjoying shooting once again with brass issues behind you.