Neck Runout Troubleshooting Help Needed

[JohnD]

“Body die to bump necks 1-2 thou and size body along with Lee Collet neck size die will produce very concentric brass with very little runout.”

This^^^! Been discussed here many times. I’ve transitioned my rifles that I expect a high level of accuracy to this system. It shows on the target.

John

 

[Murray Brook]

Body die to bump necks 1-2 thou and size body along with Lee Collet neck size die will produce very concentric brass with very little runout.

Very cost/effective way to produce very straight ammo along with a good seater die.

 

[jepp2]

Very cost/effective way to produce very straight ammo along with a good seater die.

Agree to some degree. I spent a lot of effort, time, and $ to get my sized case necks under 0.001" TIR always. Just assumed the Redding Competition bullet seating dies would do their job. Then I measured and found they are seating bullets in the 3-5 thousandths of runout. Cut that in half, but seating the bullets in 3 steps, rotating the case ~120 degrees with each step. Don't just assume, measure and confirm.

 

[Murray Brook]

Certainly agree, always measure and confirm.

 

[wagonman]

Very cost/effective way to produce very straight ammo along with a good seater die.

when Boyd Allen tells you this combo works well I listened, inexpensive die setup for a poor boy looking for less runout on ammo. oh and body die bumps shoulder and neck lee collet squeeze's neck around mandrel

 

[Chiquita]

People worry about some of the most senseless stuff

I am curious why is it senseless? I am not trying to be a dodo head.

 

[Chiquita]

In the last week I realized that my neck runouts (.002 & higher) are due to the neck bushing die. I don't know how much accuracy suffers with .002 & higher TR.

If the neck bushing dies introduce run out, what is the benefit of using them?

 

[Bc'z]

In the last week I realized that my neck runouts (.002 & higher) are due to the neck bushing die. I don't know how much accuracy suffers with .002 & higher TR.

If the neck bushing dies introduce run out, what is the benefit of using them?

I've had as high as .005 run out still group.
I'm not saying I like it that high, but it's not the end of the world if it is.

Bushing dies allow you to change neck tension, which will help with accuracy.

Are you still running a expander in your bushing die?
I only use expander button when prepping new brass with a neck only bushing die.
I wont even look at run out until after 1st firing because the use of expander button can induce run out.

 

[Chiquita]

I've had as high as .005 run out still group.
I'm not saying I like it that high, but it's not the end of the world if it is.

Bushing dies allow you to change neck tension, which will help with accuracy.

Can't I achieve the same by using the non bushing die & the 21st century expander mandrel set & adjust the neck tension that way?

Are you still running a expander in your bushing die?
I only use expander button when prepping new brass with a neck only bushing die.
I wont even look at run out until after 1st firing because the use of expander button can induce run out.

I use the sinclair expander mandrel not the button.

 

[PRR1957]

I used a Redding full length bushing sizing die in 308 Win. were I took the threaded plug that holds the bushing in the die and made a threaded sleeve to hold the threaded plug, then square faced it in a lathe and polished the end that contacts the neck bushing and lubricated it with different lubricants until I settled on high pressure red grease (Lucas) to allow the bushing to float, and it will self center on the case neck with runout of .0006”-.0009” runout. Before that, the runout was between .003”-.005”.

 

[skeeljc]

I used a Redding full length bushing sizing die in 308 Win. were I took the threaded plug that holds the bushing in the die and made a threaded sleeve to hold the threaded plug, then square faced it in a lathe and polished the end that contacts the neck bushing and lubricated it with different lubricants until I settled on high pressure red grease (Lucas) to allow the bushing to float, and it will self center on the case neck with runout of .0006”-.0009” runout. Before that, the runout was between .003”-.005”.

The threaded stem in the Redding type S bushing die can allow the bushing to float. Just back it off a quarter turn and lock it with the lock ring. You can remove the expander and still use the Redding bushing retainer.

The real problem with the bushing die is they allow the bushing to float. A floating bushing will just align on the case and keep introducing more misalignment every time it is used. A one piece FL die aligns the neck with the body every time it is used.

 

[Bc'z]

Can't I achieve the same by using the non bushing die & the 21st century expander mandrel set & adjust the neck tension that way?


I use the sinclair expander mandrel not the button.

Sure can if you like doing things twice. Lol
A lot of folks load this way and can control neck tension in finer increments.

For shit'z n grin'z I measured the run out on some rounds I was loading last nite.
New brass, Redding neck die, .288 bushing
Run out was .0015.

 

[skeeljc]

I wish Sinclair would offer their carbide expander mandrels in more sizes. I tried the 21st Century mandrels but the sizes are all over the place and not what they are marked. I use class Z plug gauges in a collet holder made by Porter's Precision Products.

 

[JFrank]

I really have not seen any difference on paper shooting rounds with small amounts of run out, now that doesn't mean someone else had an opposite experience i just quit worrying about it and sold my gage.
Im also not in the camp of in bore yaw .
J

 

[JMayo]

Least used piece of equipment is a concentricy guage ....
Unless it's just stupid crooked, shoot it.

 

[Retired Grunt]

Least used piece of equipment is a concentricy guage ....
Unless it's just stupid crooked, shoot it.

I bought one last year and used it once. There was a thread a long time ago about them, I learned if you are using quality Die's you won't see much run out.

 

[skeeljc]

A concentricity measuring device is for evaluating your process, not sorting finished product.

 

[Uncle Ed]

If you do not check your cases for neck thickness variations and check the resized case neck for runout you will never know "WHY" you do have runout problems. Why check runout after loading the cases and wonder where the runout came from.

Tech Line & Tips (FAQs)​

https://www.redding-reloading.com/tech-line-a-tips-faqs/146-concentricity-problems

Concentricity Problems​

a.k.a Neck Runout With Bottleneck Cases

The concentricity, or neck runout, of loaded cartridges is an important consideration for reloaders and especially the varmint or target shooter.
There are many factors that can cause or contribute to neck runout during the reloading process and many reloaders who have not dealt with the problem before quickly blame the sizing or seating die.
While the dies may be at fault or have a contributing defect, modern CNC machinery and reamers that cut the body, shoulder, and neck simultaneously make such occurrences rare. Most problems are related to the brass itself and its uniformity both in terms of hardness and thickness and how much it is being stressed in the reloading process.

We have conducted many tests over the years on the various factors contributing to concentricity problems with bottleneck cases. We have repeatedly found a definite correlation between the uniformity of the brass (or lack of it) and the resulting concentricity of the neck to the body of the case.

An interesting experiment also revealed that neck turning of brass that was intentionally sorted as non-uniform, showed little or no concentricity improvement when used in standard S.A.A.M.I. spec chambers. Conversely brass that was sorted and selected for uniformity remained uniform and concentric with or without a neck turning operation.

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If you have a runout gauge and a neck thickness gauge you don't need a black felt tip marker to tell you that you need good gauges.

 

[PRR1957]

The threaded stem in the Redding type S bushing die can allow the bushing to float. Just back it off a quarter turn and lock it with the lock ring. You can remove the expander and still use the Redding bushing retainer.

The real problem with the bushing die is they allow the bushing to float. A floating bushing will just align on the case and keep introducing more misalignment every time it is used. A one piece FL die aligns the neck with the body every time it is used.

The problem with wanting the neck bushing to float in a Redding die is that the plug surface were the bushing bears up against is ruff and the bushing wasn’t allowed to center holding the bushing in whatever position it would first contact the plug, for what better term to describe the plug. When I said I faced in a lathe, was to just clean it up and makes sure it was square. I then polished it while still being healed in the lathe, starting with 800 grit and working up to 3000 grit. All I know is made a big difference.

 

[Richard Jones]

^^^ You've seen this big difference on target?