Runout Again

[jpistolero02]

This runout business is driving me nuts. Let me preface this by saying I don’t know that I can tell any difference for my practical purposes of a bullet with more runout than another. This is more or less me being pissed I have a flaw somewhere in my reloading process. Maybe one of you guys can point me in the right direction. Here is my process for any round but in this case let’s focus on the 6BR.

1. Co-Ax Press
2. Deprime brass with deprimer only
3. Stainless tumble
4. Anneal
5. Full length size with Forster FL sizer with expander removed
6. Measure neck runout with Sinclair gauge. Most brass 0-.001 runout. So maybe some slight runout induced in sizing step.
7. Lube necks with dry lube powder and run 20th Century titanium expander die through the cases. Maybe slightly more runout induced. Most still now below .002.
8. Seat Berger 105 with SAC seater and measure runout. Some are now measuring .007. I can get similar results with Forster comp seater.

 

[nn8734]

This runout business is driving me nuts. Let me preface this by saying I don’t know that I can tell any difference for my practical purposes of a bullet with more runout than another. This is more or less me being pissed I have a flaw somewhere in my reloading process. Maybe one of you guys can point me in the right direction. Here is my process for any round but in this case let’s focus on the 6BR.

1. Co-Ax Press
2. Deprime brass with deprimer only
3. Stainless tumble
4. Anneal
5. Full length size with Forster FL sizer with expander removed
6. Measure neck runout with Sinclair gauge. Most brass 0-.001 runout. So maybe some slight runout induced in sizing step.
7. Lube necks with dry lube powder and run 20th Century titanium expander die through the cases. Maybe slightly more runout induced. Most still now below .002.
8. Seat Berger 105 with SAC seater and measure runout. Some are now measuring .007. I can get similar results with Forster comp seater.

How does your ammo perform? Does it meet your expectations for precision and (if you have a requirement for it) minimal mean muzzle velocity?

 

[straightshooter1]

This runout business is driving me nuts. Let me preface this by saying I don’t know that I can tell any difference for my practical purposes of a bullet with more runout than another. This is more or less me being pissed I have a flaw somewhere in my reloading process. Maybe one of you guys can point me in the right direction. Here is my process for any round but in this case let’s focus on the 6BR.

1. Co-Ax Press
2. Deprime brass with deprimer only
3. Stainless tumble
4. Anneal
5. Full length size with Forster FL sizer with expander removed
6. Measure neck runout with Sinclair gauge. Most brass 0-.001 runout. So maybe some slight runout induced in sizing step.
7. Lube necks with dry lube powder and run 20th Century titanium expander die through the cases. Maybe slightly more runout induced. Most still now below .002.
8. Seat Berger 105 with SAC seater and measure runout. Some are now measuring .007. I can get similar results with Forster comp seater.

I also use a Forster FL sizing die with expander ball removed in a Forster Co-Ax and anneal my brass before sizing. I had my Forster FL sizing die reamed by Forster (cost was $15) out to my designated dimeter so that my expanding mandrel doesn't have to do much work and that tends to keep the runout very low (like I tend to get neck runout <.001 and most often at ~.0005". The other thing I do, which you might want to change is to clean your brass AFTER you anneal as annealing leaves a sticky/rough oxidation on the surface that tends to make the sizing die pull on the brass more than needs be (have some effect on the neck runout, IMHO).

However, going to .007 with a neck runout from below .002", tells me there's something going on with your seater die and very well could be the seating pin in it that's not allowing the pin to sit square on the bullet's ogive. If your Berger's are the 105 VLD's, then the seating stem needs to be one that works with a Secant Ogive, otherwise your runout is common when the right seating stem isn't being used.

 

[PinesAndProjectiles]

How does it shoot?

I had a run out gauge and sold it because it did nothing to improve my accuracy as a shooter.

Best thing I ever did.

 

[jpistolero02]

My rifle is shooting more than fine. I am trying to hone my skills to maybe compete when I have more time, but I can hold MOA or less to any distance I will need to shoot. It’s really me just verifying my process. So far the numbers and results on target are there, so I guess I am just barking up the wrong tree. Thanks for letting me talk it out.

 

[Cascade Hemi]

What die rings? I had something similar happen and it was the rings. The CoAx is sensitive to the flatness of the die rings and how true the face of the ring is to the threads. Hornady rings were the flattest.

 

[918v]

When you size the case in a FL sizer and then expand the neck back out the neck gets harder and will warp a little. This is one factor that causes runout. Your seater die will not force the case neck to hold the bullet in a way it doesn’t want to.

You could get a die that sizes less or increase the annealing time or both.

 

[straightshooter1]

What die rings? I had something similar happen and it was the rings. The CoAx is sensitive to the flatness of the die rings and how true the face of the ring is to the threads. Hornady rings were the flattest.

Very true. And this is the reason I rotated my die in my Co-Ax until it produced the best results, then I made a reference mark on the die so after removing the die and putting it back in it's in the same position.

I recently got Cortina's new expanding mandrel die that fits tight at the bottom of the case and he's made it a point to have the correct flat surface of the ring pushing against the press as it's that surface where the threads are aligned to make the die work square. The results I got were pretty good, where my neck's runout is consistently <.001 after expansion. And this is with case necks for a 6.5 PRC that are being moved by a Forster FL sizing die by .008" (more than I typically like a die to do).

 

[jpistolero02]

I am using Forster rings.

 

[salks]

2 things you may want check. Make sure your die is not bottoming out on the shell holder. Make sure the shell holder is bolted correctly with the springs facing out. I am not sure if it will help but it may. I have never noticed run out cause a huge problem but It drives me nuts because i think it should not be there as well.

 

[FredHammer]

Did a blind test experiment mid 2000s where I didn't know which runout batch I was shooting. .009 batch shot as good as .001 batch. Sold that OCD runout gauge.

 

[straightshooter1]

Did a blind test experiment mid 2000s where I didn't know which runout batch I was shooting. .009 batch shot as good as .001 batch. Sold that OCD runout gauge.

. . . and all the groups were at 1 MOA!

 

[Dstoenner]

I don’t read here that you turned your necks. My personal solution was turned necks. Forster sizing die honed to .003 less than a loaded round then seated with a Redding micro seater. The spring in the Redding seater is the secret sauce. My seated rounds run about 60% .001, 30%, .002 and rest .003 or .004. I use the 3,s and 4’s for scope zero check and velocity check of this batch.

I also set up the sizing die to kiss the shell holder and then using Redding match shell holders to control the set back of the neck. This then gives me very even cases to go into the seater.

David

 

[jpistolero02]

Correct, I have not turned any necks.

 

[straightshooter1]

Correct, I have not turned any necks.

Variations in neck thickness can account for some of the runout reading you're getting. How much is involved depends on the quality of one's brass. I meant to mention this before, as I do turn my necks, mostly because I tend to be a perfectionist.