Loaded runout vs neck runout before loading

[dstoenner]

So the hazard of being an retired engineer is that everything can be an experiment. This actually didn't start out to be an experiment but half way some case prep I came up with the idea. I thought I would share my results.

Let me set the stage. I currently shoot a 260 Remington for F-Class. I have one more season left on this barrel and then it will be time to rebarrel. I am also aging and so 60+ rounds of 260 recoil wears thin sometimes. I wanted to go to a 6mm caliber so I choose a 6x47 Lapua as my next choice. So I bought a new barrel, 2 boxes of Lapua brass. This winter's project has been to get all of the brass fully fire formed and work up a tentative load. Along the way I was able to snag some 1X fired 6.5x47 brass as my 3rd box of brass.

In doing the brass prep I was seeing that it was doing better on the resizing effort than the unfired brass had been. So I got to wondering what was the neck runout distribution. So when I was through with the entire lot of being fully prep'd ready to load, I measured the brass and left it in the sorted order. That was when I got the second phase of my idea to then see what the runout distribution per initial neck runout before loading looked like.

I have never seen anybody write this up so I thought I would. I don't think it is earth shattering but it is interesting, at least to me. So here goes for the data.

The load is 107 SMK at 2.620. That seats the bullet so that the top of the boattail is flush with the shoulder neck junction. The seating die is a Redding Competition micrometer seater with a VLD stem

1) Neck runout <= 2 mil (22 cases)

Loaded runout 11 - <=2 mil
Loaded runout 10 = 3 mil
Loaded runout 1 = 4 mil

2) Neck runout = 3 mil (26 cases)

Loaded runout 2 <= 2 mil
Loaded runout 13 = 3 mil
Loaded runout 7 = 4 mil
Loaded runout 5 = 5 mil

3) Neck runout = 4 mil (17 cases)

Loaded runout 1 <= 2 mil
Loaded runout 5 = 4 mil
Loaded runout 11 = 5 mil

4) Neck runout = 5 mil (21 cases)

Loaded runout 1 = 3 mil
Loaded runout 4 = 4 mil
Loaded runout 9 = 5 mil
Loaded runout 6 = 6 mil
Loaded runout 1= 7 mil

5) Neck runout = 6 mil (7 cases)

Loaded runout 1 = 5 mil
Loaded runout 6 = 6 mil

6) Neck runout = 7 mil (2 cases)

Loaded runout 1 = 6 mil
Loaded runout 1 = 7 mil

I can see 2 observations in this data.

1) Generally the loaded round will have no better runout than the case neck runout before seating. I think we all figured that as a no brainer. The old adage you don't get something for nothing.

2) Some cases did get better. I think that a case might be straighter than the neck runout might indicate so in some rare cases you can get better runout seating a long bullet that can pull things around in a chamber type seating die (At least that is my theory).

Hope this spurs some thoughts for all of the community

David

 

[Bart B.]

Don't know what sizing die you use, but my 308 Win fired cases ended up with straightest necks (least runout) using gelded FL dies (no expander balls) with necks honed out to .002" smaller than loaded round neck diameter.

Expander balls tend to bend case necks a little bit.

 

[dstoenner]

Don't know what sizing die you use, but my 308 Win fired cases ended up with straightest necks (least runout) using gelded FL dies (no expander balls) with necks honed out to .002" smaller than loaded round neck diameter.

Expander balls tend to bend case necks a little bit.

Bart

I guess I wasn’t clear enough in the beginning. These cases were the result of taking 6.5x47 cases and in 2 steps converting them to 6x47 cases. Then neck turning them and a final size to be loaded to fire form them.

I use a Whidden FL bushing die and these cases when now fireformed came out mostly 1 mil neck runout. There are a few 3 mil now which I am betting were from the 6 and 7 group.

Like you say I generally don’t have cases with this much runout to measure this effect. Even out of the box Lapua doesn’t have this much runout before the first loading.

I also agree that the expander ball pulls necks out of being concentric. I found that out the hard way when I couldn’t get my 260 to get low loaded runout. Chasing down every step I found the cases going into be sized with 1 mil or so coming out 3 to 4. I took the expander ball out and bingo the culprit was found.

David

 

[Shynloco]

Bart


..... I took the expander ball out and bingo the culprit was found.

David

David,
Though I agree that the Expander Ball can be the culprit, I would offer that often it is the Seater Stem that is bent to which the Expander Ball is connected. A good way to find out is to remove the Seater Stem completely and run the casing through the die. This also checks the concentricty of a casing run through a good die. If the die is good, checking the concentricty of the casing just run through the die, should be very good....002 or less. I also load and shoot a 260BR Rem and I've found that the Seating Stem can oft times be the problem when using an expander ball. Learned about this issue after speaking to a Redding Tech who helped me improve my runout in various (Redding Dies) calibers by testing the Seater Stem itself. Depending on what I'm reloading for, I use both fixed sized dies as well as "S" Dies. With "S" dies, the Seater Stem won't make much of a difference.

Alex

 

[Dusty Stevens]

2 questions-
1. Did you turn your necks?
2. Whats the result on target?
Dont overthink things. Will you be able to see .001 runout? Expander balls are a bad idea no matter what the case as you found out. In your particular discipline could you pick out a case with .005 runout in a group with .003 runout or will the wind move the bullet more than that? Sometimes overthinking things in the winter takes the fun out of shooting

 

[dcali]

Always nice to see some data to back up one’s hunches. Thanks for the write up.

 

[jepp2]

Don't know what sizing die you use, but my 308 Win fired cases ended up with straightest necks (least runout) using gelded FL dies (no expander balls) with necks honed out to .002" smaller than loaded round neck diameter.

Expander balls tend to bend case necks a little bit.

This mirrors my experience. The only way I have found I can use expanders and not have them negatively neck runout:
- lube the inside of the case neck with a good quality lube (graphite doesn't do it for me)
- use a carbide expander
- set the expander high, so it passes through the case neck as soon as the case neck exits that portion of the die
- limit the amount of expansion to 0.002 or less that the expander has to do. This trumps the above 3 items. If my expander has to expand the case neck 0.0025 or more, it will significantly impact the case neck straightness.

And on normal FL sizing dies, I have to hone the case necks to limit the amount the expander has to increase the case neck. When I hone my dies, I target having the expander only have to increase the case neck 0.0005 to 0.001".

 

[muleman69]

This mirrors my experience. The only way I have found I can use expanders and not have them negatively neck runout:
- lube the inside of the case neck with a good quality lube (graphite doesn't do it for me)
- use a carbide expander
- set the expander high, so it passes through the case neck as soon as the case neck exits that portion of the die
- limit the amount of expansion to 0.002 or less that the expander has to do. This trumps the above 3 items. If my expander has to expand the case neck 0.0025 or more, it will significantly impact the case neck straightness.

And on normal FL sizing dies, I have to hone the case necks to limit the amount the expander has to increase the case neck. When I hone my dies, I target having the expander only have to increase the case neck 0.0005 to 0.001".

When you say hone dies, how do you go about this? Do they make undersize expander balls? (just asking)

 

[dstoenner]

2 questions-
1. Did you turn your necks?
2. Whats the result on target?
Dont overthink things. Will you be able to see .001 runout? Expander balls are a bad idea no matter what the case as you found out. In your particular discipline could you pick out a case with .005 runout in a group with .003 runout or will the wind move the bullet more than that? Sometimes overthinking things in the winter takes the fun out of shooting

Dusty,

Yes I did turn my necks. Just so everybody understands what went into these cases before I measured neck runout.

1) Purchased 100 cases from a member on this site. I was claimed they were 1X fired, cleaned in SS media (I can verify that as I found a pin inside one of the cases) sized and annealed.

2) I weight sorted them and found 95 that were within 1 gn of each other. It is then these 95 that started to the process to reform them to 6x47.

3) I first took out the sizing bushing and used my Whidden FL 6x47 Lapua sizing die with a Redding .010 competition shell holder. Having checked the headspace they were right where my unfired cases were. I then did the first step. This sized the neck down to about .250. I used imperial wax put on by my hands for each case.

4) I then put my .267 (biggest bushing I own right now) in with the expander ball. (befiore you throw rocks at me wait for the next steps). I now sized them down and re-expanded the necks so the would be ready for step 5. I used imperial wax on the inside of the neck put on with a q-tip and more sizing wax put on the out side of the neck area.

4) I now turned them with a Forester had neck turner to clean up the neck. This ended up with necks at about .013 per side.

5) I then resized these with my die using a .266 sizing bushing with no expander ball. Again more sizing wax was reapplied to the neck area.

6) They now went into the vibratory cleaner to get everything ready for loading.

7) Now they were primed.

It was at this point I did all of the neck runout sorting. I had sampled what the runout was doing at the neck turning level and saw they were straighter at this point than the previous unfired cases but I was also learning how to get the steps right.

HTH explain when and where I did all of this.

to your second question, I didn't even fire the high runout for the target, just used them with the Magnetospeed for getting an idea of what velocity I was getting. Then the rest were fired for groups. At 100 yards I have not found rounds that have runout up to 3 mils to be any real different than 1 mil. Since these were fired with only about 200 rounds down range and I just took a SWAG at powder, 38 gn H4350 for the 107's, The groups were in the .5 to .750 range. Not great but still really good for a fireforming.

Yes I completely agree that rounds with 3 to 4 mil runout at a 1000 probably just as accurate as 1 mil rounds since I am still learning how to really read the mirage and wind and keep close to the 10 ring.

I just received my first long range F-Class classification of Sharpshooter. I have a LOT to learn. But you are never too old to acquire new skills.

David

 

[muleman69]

David,
Though I agree that the Expander Ball can be the culprit, I would offer that often it is the Seater Stem that is bent to which the Expander Ball is connected. A good way to find out is to remove the Seater Stem completely and run the casing through the die. This also checks the concentricty of a casing run through a good die. If the die is good, checking the concentricty of the casing just run through the die, should be very good....002 or less. I also load and shoot a 260BR Rem and I've found that the Seating Stem can oft times be the problem when using an expander ball. Learned about this issue after speaking to a Redding Tech who helped me improve my runout in various (Redding Dies) calibers by testing the Seater Stem itself. Depending on what I'm reloading for, I use both fixed sized dies as well as "S" Dies. With "S" dies, the Seater Stem won't make much of a difference.

Alex

I have Redding dies and have removed my stem and checked cases with good results. What is the next step new stem, collet dies or bushing die?

 

[jepp2]

When you say hone dies, how do you go about this?

I use laps that I get from MSC. I have used both blind hole and thru hole laps. I prefer through hole. An example is:
https://www.mscdirect.com/product/details/05060165

Pick the correct opening range when you buy.

I'm just a battery powered drill method since I don't have fancier equipment. To help keep the lap centered (although might not be totally necessary) I make an undersize bushing from electrical tape. Don't slop lapping compound on the tape or you could be lapping where you don't want to. I start with 240 grit Clover silicon carbide grease lapping compound. Normally finish with 600 grit. It has worked very well for me. But before you start, know what diameter you want to finish with and check your progress. Material removal is slow as the dies are very hard. I tried flex hones at first, but they don't work.

Unless you are using a carbide expander, you can just sand them down. I always polish them as a minimum.

Here is a blind hole lap I have used:

 

[Bart B.]

When you say hone dies, how do you go about this? Do they make undersize expander balls? (just asking)

Forster hones their die necks for $12 each. Any decent 'Smith could do it.

Use a Flexhone brush correctly in an electric drill and a hole micrometer to do and measure your own dies.

I would not use undersize expander balls. Undersize case mouths will be smaller and scrape off bullet jacket copper unbalancing them. The extra force needed to seat bullets can bend case necks.

 

[Bart B.]

In your particular discipline could you pick out a case with .005 runout in a group with .003 runout or will the wind move the bullet more than that?

Rule 1 in testing ammo: test only in stable atmospheric conditions. Half hour before sunrise is best. Cool air is very stable.

One of the military rifle team tests with M14NM rifles in machine rests showed M118 match ammo with .003" or less shot with equal accuracy. Ammo with more run out didn't do as well. Groups open up an MOA up to about .007" runout then no more with greater runout. Some lots of M118 had up to .008" runout.

Orientation of rounds bullet high point the same in the chamber produced good accuracy. I've done this with 7.62 Garands and got the same good results.

I've seen new case 308 Win ammo with .004" max runout and 3/10 grain charge spread shoot about 1/2 moa at 600 yards for 15 to 20 shots. Some ammo measurements don't need zero spread.

 

[dstoenner]

I have Redding dies and have removed my stem and checked cases with good results. What is the next step new stem, collet dies or bushing die?

If you don't have an expander ball on your stem then I don't understand how the stem is effecting anything, unless your stem is actually bottoming out against the case web inside.

I have tried the Lee collet die on turned neck 260 cases and not found it to be a reliable solution. My solution I have arrived at through a lot of experiments is a Whidden FL bushing die. I use it with the stem but no expander. I set the stem body to the point of stopping on the bushing and then backing it out about 1/8 turn. That way the bushing can float to center itself. Once adjusted I check to see if I can faintly here it rattle.

I turn all of my necks on all of my cases, even LC cases for my AR15 and both of my Garands. Consistency is what I strive for.

 

[dstoenner]

Rule 1 in testing ammo: test only in stable atmospheric conditions. Half hour before sunrise is best. Cool air is very stable.

One of the military rifle team tests with M14NM rifles in machine rests showed M118 match ammo with .003" or less shot with equal accuracy. Ammo with more run out didn't do as well. Groups open up an MOA up to about .007" runout then no more with greater runout. Some lots of M118 had up to .008" runout.

Orientation of rounds bullet high point the same in the chamber produced good accuracy. I've done this with 7.62 Garands and got the same good results.

I've seen new case 308 Win ammo with .004" max runout and 3/10 grain charge spread shoot about 1/2 moa at 600 yards for 15 to 20 shots. Some ammo measurements don't need zero spread.

I am blessed to have a 100 yard indoor range 2.1 miles from my front door. So all of my ammo development is no wind. We do get some mirage on high humidity days but if you wait for the muzzle basts to flatten out you still can get good results.

 

[muleman69]

What

If you don't have an expander ball on your stem then I don't understand how the stem is effecting anything, unless your stem is actually bottoming out against the case web inside.

I have tried the Lee collet die on turned neck 260 cases and not found it to be a reliable solution. My solution I have arrived at through a lot of experiments is a Whidden FL bushing die. I use it with the stem but no expander. I set the stem body to the point of stopping on the bushing and then backing it out about 1/8 turn. That way the bushing can float to center itself. Once adjusted I check to see if I can faintly here it rattle.

I turn all of my necks on all of my cases, even LC cases for my AR15 and both of my Garands. Consistency is what I strive for.

What I meant was I resized a case with stem and ball removed and got good concentric necks. So that would mean stem, ball or both are the problem . So what to try next? New stem or carbide ball or both? Is there any way of checking before I place an order?

 

[muleman69]

Forster hones their die necks for $12 each. Any decent 'Smith could do it.

Use a Flexhone brush correctly in an electric drill and a hole micrometer to do and measure your own dies.

I would not use undersize expander balls. Undersize case mouths will be smaller and scrape off bullet jacket copper unbalancing them. The extra force needed to seat bullets can bend case necks.

So if the die was honed out large enough there would be no need for expander ball ,is that correct? ( providing neck thickness is close) Just asking?

 

[Bart B.]

So if the die was honed out large enough there would be no need for expander ball ,is that correct? ( providing neck thickness is close) Just asking?

Yes.

That is how most bushing dies work.

Such dies have been used since the 1960's by many match winners and record setters as well as match bullet makers testing their stuff for quality.

 

[Dusty Stevens]

Honing a die is like only having one bushing permanently hoping conditions never dictate you changing neck tension unless you have an assortment of expander balls to plow back thru the neck

 

[muleman69]

Honing a die is like only having one bushing permanently hoping conditions never dictate you changing neck tension unless you have an assortment of expander balls to plow back thru the neck

I here you, guess I better figure on ordering bushing die