FL sizing in two steps vs. one step

[bobm]

Having 50 once fired Nosler cases on hand, I measured neck walls and found four with a very consistent .0132 thickness. I sized them using a variety of dies and some steps outlined here. All hunting bullets seated with the Redding Competition seater die. All four assembled rounds were checked for run out in two places, shank and near the tip, and recorded in TIR. A .309 bushing was used.

Not one method stood out as better than the other. Take your pick. Cut the numbers in half for actual centerline run out...ie.....concentricity.

Redding Comp. bushing die.................SHANK .0010_____TIP .0038
Redding S neck bushing die.................SHANK .0008_____TIP .0040
Redding S neck followed by BODY die.........SHANK .0010____TIP .0065
Redding standard FL die w/button......SHANK .0010____TIP .0045

EDIT: added another step with an interesting observation. Two assembled cases gave almost the same readings. New 168gr. SMK used.

Redding BODY die followed by Redding S neck bushing die. SHANK____.001 (both)
TIP _____.0025 & .0028 TIR

Nosler brass is good stuff.

 

[mikecr]

There is nothing wrong with separate body-bushing-mandrel sizing.
My loaded ammo with this is as good and straight as anybody's.

I'm sure a custom to your fired brass FL sizing die is fine as well, but I would never FL size my necks.
There is a FL die, that does that.
There is a bushing-body FL die, which includes shoulder in the bushing.
There is a body-neck bushing die, that does not FL size (partial neck sizing).
As separate dies, both the neck die and the body die can be custom (mine are).

As far as whatever a mob does, it doesn't matter.
Do what your own objective & logical thinking leads to.

 

[AJC]

I jumped off the bus at the honed forester die and mandrel to set neck tension. They had a great article on this site that described its value and I liked the simplicity. Maybe I'm just boring.

 

[Dave M.]

There is a widespread opinion that the best way to FL size your brass is to (a) resize the neck with a bushing neck sizing die (usually Redding) and then (b) resize the body of the case with a body die (people recommend also Redding for this operation). The rationale behind this process is that it should produce more concentric rounds in comparison to running a standard FL die (without expander ball+expanding the neck with a mandrel in a separate step).

The 2-step process is obviously less time efficient, so is it worth extra effort?
I didn't find answer in this thread

Two step sizing question...

So I was reading an article over on the Rifleman's Journal, where an experiment was performed that examined order of sizing operations versus concentricity readings. The findings showed that sizing a case by taking the neck down in two steps first sizing with a bushing neck die then sizing...

forum.accurateshooter.com

I’ve never heard of this theory, nor do I subscribe to it. I feel it is impossible to make a more accurate round that you can get using a single step custom full length Resizing die. Do you have any proof of this theory?
dave

 

[Old Tanker]

An open question for all of you. Why wouldn’t a full length bushing die fit this need? I have an L.E. Wilson FL Bushing die that works very well for my .223 loads. Thinking about getting one for my 6.5CM and my .308.

 

[marchx]

@Dave M. if I had a proof, I wouldn't be posting this thread. I know several F-class or LR shooters who follow this path. I used to do the 2-step process, but I got back to an FL die+carbide mandrel after that for time saving purposes.

 

[marchx]

An open question for all of you. Why wouldn’t a full length bushing die fit this need? I have an L.E. Wilson FL Bushing die that works very well for my .223 loads. Thinking about getting one for my 6.5CM and my .308.

Do you run a mandrel after that or not?

 

[Bc'z]

Do you run a mandrel after that or not?

No need for a mandrel if using the appropriate bushing that gives the best result on paper.
Isn't your bullet a mandrel so to speak?
I personally use Redding and Wilson FL bushing dies and seat with a Redding competition seater.
Just sold my concentricity gauge too.

 

[fatelvis]

I think concentricity is over rated, and people obsess over it too much.

 

[marchx]

No need for a mandrel if using the appropriate bushing that gives the best result on paper.
Isn't your bullet a mandrel so to speak?
I personally use Redding and Wilson FL bushing dies and seat with a Redding competition seater.
Just sold my concentricity gauge too.

Valid point. This is something I am going to test- mandrel vs bushing. I will compare seating force and velocity.

 

[Fuj]

Valid point. This is something I am going to test- mandrel vs bushing. I will compare seating force and velocity.

I have already tested for my own needs. A mandrel gave me the
the best results for my rifles. I also like the fact that if there is any
internal neck imperfection, I'd rather have a hardened mandrel
address it, then the bullet I'm competing with. As is said....Talk
to 10 different shooters, get 10 differing results.

 

[marchx]

I have already tested for my own needs. A mandrel gave me the
the best results for my rifles. I also like the fact that if there is any
internal neck imperfection, I'd rather have a hardened mandrel
address it, then the bullet I'm competing with. As is said....Talk
to 10 different shooters, get 10 differing results.

That is also my rationale. As to whether I am right on this, that is another question and my primary reason for starting this thread.

 

[bobm]

Last but not least, I repeated this little test with the standard neck size die. This once fired Nosler brass was not fired by me, but found at the range left behind by another shooter. It was easy to pick a few from the bag of 50 this morning and find a couple with near perfect .0132 wall thickness again. Each case got a very light ID neck deburring. Again, two cases were measured, full neck sized and 168gr. SMK's were seated.

Redding standard neck size die w/expander button.

SHANK____.0008 & .0005....yes, that good.
TIP________.0028 & .0025

Measurements are TIR. (for those unfamiliar, Total Indicator Reading)

I regret not using SMK's for the whole experiment, but I am not doing it over.

 

[watercam]

I put my brass in the sizing die and run it up in there & leave it there while I lube the next with Imperial. The time this takes helps prevent spring back of the brass. I use custom dies and don't have a problem with run out. I shoot mostly SR BR and never found it necessary to neck size 1st. I did pick up a neck die in trade some years back but never used it. If you shoot 6ppc and decide you want one, shoot me a PM.

Regards
Rick

Now this makes sense. No extra time involved and your brass is sized more completely. Have never had issues with one pass using Redding S-type Bushing dies.
I DO rotate my bullets 180º when seating and my measured run-out is 0.000"-0.001" as opposed to 0.000"-0.003" w/o rotation.
FWIW

 

[JFrank]

Do you own a concentricity gauge? Have you ever been to a sanctioned short range benchrest match?

Boyd
I’m sensing frustration in your text ? Maybe I’m wrong.
Jim

 

[JMayo]

Boyd
I’m sensing frustration in your text ? Maybe I’m wrong.
Jim

I kinda like his question. There is so much "speculation" .. Chit that just pops into some ones head...
Experience, not thoughts & speculation, need to be the answer givers

 

[rogina]

Testing is usually the only way to know with any certainty whether a potential approach is worth incorporating into the reloading scheme. The caveat that may come into play is when the differences between two approaches are not "in your face" obvious, as they often turn out to be. It can sometimes be much more difficult to reliably demonstrate whether some particular approach provides an advantage or improvement over another if the difference is fairly small. For example, a slight improvement in the consistency of neck tension might mean slightly more consistent velocity. Such an improvement might only be worth a point or two per match. So it wouldn't necessarily be something from which you could draw a definitive conclusion in a single test. Nonetheless, it is still possible over time to reach a valid conclusion. For approaches where the difference might be very small (but not zero), at times we still have to go with our gut instinct to make a final decision. Best of luck with the testing!

I agree with Ned. Do your own testing, then you will believe the results and not be questioning everyone else's results.

 

[Fuj]

You also have to bring in the subject of annealing in any of
the test results. Some mention spring back, but that should
not be the case with a proper anneal. When running a mandrel
after annealing, I'll get a few cases that push harder then normal,
and I'll set them aside for foulers.

 

[mikecr]

Experience, not thoughts & speculation, need to be the answer givers

Do you imagine that we've reached the end of all learning here?
That we should concede to declarations with no more basis than call to authority fallacies?

 

[Murray Brook]

I use a Redding body die to size my case and bump the shoulder then a Lee collet die to size the neck followed by a Forster seating die to seat the bullet. I can say after testing that my overall run-out had been reduced vs using a standard FL die. What I can't say is that I see better results on paper, ( at least in the shooting I do 100-300 yrd ) but that is another can of worms. JMO