NK vs FL resize

[260 Rem]

Let’s start a new thread on the topic so not to derail the case prep thread. Iclund has started with some data and hope he will share in this thread as well?

[260 Rem]

Just for interest this AM, I used some H380 to compare fill volumes ... on a piece of 11X fired 6.5 X 47L (NK sized only), I NK sized, installed a new primer, filled to capacity with 20 “taps” to settle powder. Then, FL sized with a Redding body die, same fill technique.
Difference in volume by weight was 0.6 grains less in FL resize case.

[fps plus]

Try filling with water ,eliminating the #tap and use the same piece of brass resized both ways

[FallAirFever]

Hey 260,
Thank you for starting this, I was thinking of doing it as well. I'm glad my questions were answered before it took a turn. But I am interested to hear more reloaders thoughts on sizing.

I have neck sized and FL sized both seem to work well for my needs but if there is more options for the average shooter I'm all ears.. .

[elkhunter11]

I do both, depending on the application. Accuracy wise, the differences are usually small, if even noticeable, as even when I use a FL die, I adjust the die to barely move the shoulder at all, just enough so that the cartridges chamber easy. Velocity wise, I may see a slight difference with the smaller capacity cases, but no noticeable difference with my 7mmstw. Probably the biggest difference, is that the case life is better when I neck size with a bushing die , compared to using a regular non bushing FL die. I have never used a bushing FL die, so less working of the neck due to the bushing die, is likely the biggest factor.

[FallAirFever]

Originally Posted by elkhunter11

I do both, depending on the application. Accuracy wise, the differences are usually small, if even noticeable, as even when I use a FL die, I adjust the die to barely move the shoulder at all, just enough so that the cartridges chamber easy. Velocity wise, I may see a slight difference with the smaller capacity cases, but no noticeable difference with my 7mmstw. Probably the biggest difference, is that the case life is better when I neck size with a bushing die , compared to using a regular non bushing FL die. I have never used a bushing FL die, so less working of the neck due to the bushing die, is likely the biggest factor.

Couple questions, who makes bushing dies and what do they do? Do they neck and bump the shoulder as well?

[260 Rem]

I know that the volume is most accurately measured using water...but I did a bunch of “measuring” this afternoon...both with H380 (fine ball) and H4350 (extruded/stick)...just so I could make some generalizations to kick start some discussion/speculation.

Generalized, for my 6.5 X47L fired in a relatively tight chamber and resized with “close to chamber fit” Redding (NK & FL) dies...after 11 NK size reloads, the case volume increased by approximately 1.4% over FL sizing.
It would be reasonable to assume that the volume increase in a looser SAAAMI chamber (say a 308) would be larger (somebody should check)?
Assuming that the growth in volume is incremental, it could be argued that a “tickle” more powder should be added to each NK size reload to maintain constant velocity. Well, that’s the theory

[elkhunter11]

Originally Posted by FallAirFever

Couple questions, who makes bushing dies and what do they do? Do they neck and bump the shoulder as well?

Not all manufacturers make the case necks the same thickness, so a regular non adjustable die typically squeezes the neck down more than required, which work hardens them more. With a bushing die, you choose a bushing that squeezes the neck down just enough to provide the proper neck tension, which provides optimum accuracy, and minimizes work hardening of the neck. I use Redding Match die sets that include neck bushing dies and the competition bullet seating die as well. These dies are not cheap, and you need to buy bushings as well, but they do work well.

[260 Rem]

Originally Posted by FallAirFever

Couple questions, who makes bushing dies and what do they do? Do they neck and bump the shoulder as well?

I have both bushing NK and FL sizer dies made by Redding. NK dies resize the neck only, FL resize the neck and “full” body. I think Hornady May also make bushing style dies?
EDIT: ADD: The Redding match die sets include a full body die as well.

[elkhunter11]

Originally Posted by 260 Rem

I know that the volume is most accurately measured using water...but I did a bunch of “measuring” this afternoon...both with H380 (fine ball) and H4350 (extruded/stick)...just so I could make some generalizations to kick start some discussion/speculation.

Generalized, for my 6.5 X47L fired in a relatively tight chamber and resized with “close to chamber fit” Redding (NK & FL) dies...after 11 NK size reloads, the case volume increased by approximately 1.4% over FL sizing.
It would be reasonable to assume that the volume increase in a looser SAAAMI chamber (say a 308) would be larger (somebody should check)?
Assuming that the growth in volume is incremental, it could be argued that a “tickle” more powder should be added to each NK size reload to maintain constant velocity. Well, that’s the theory

Then again, the cases do stretch as they form to the chamber when fired, so which volume actually determines the combustion chamber volume, the sized case volume, or the fired case volume? Or is it somewhere in between? Is the growth really incremental, or does the case stretch more during the first firing, and taper off with successive firings? Or does the case stretch the same amount on firing, and spring back less with each firing ?

[260 Rem]

Originally Posted by elkhunter11

Then again, the cases do stretch as they form to the chamber when fired, so which volume actually determines the combustion chamber volume, the sized case volume, or the fired case volume? Or is it somewhere in between? Is the growth really incremental, or does the case stretch more during the first firing, and taper off with successive firings? Or does the case stretch the same amount on firing, and spring back less with each firing ?

Only measuring can answer definitively, but by best guess is the biggest “stretch” occurs on first firing. On my 11x fired brass...after I FL sized, at the case/shoulder junction, the fired brass is .006” larger than factory.
This “first stretch” factor may also support the “fireform before you tune” argument.

[260 Rem]

FALLAIRFEVER - if I was starting over again, I would buy a single Redding Type S FL die (with bushings) for resizing, and a Wilson in-line seater to seat bullets.

[elkhunter11]

Originally Posted by 260 Rem

Only measuring can answer definitively, but by best guess is the biggest “stretch” occurs on first firing. On my 11x fired brass...after I FL sized, at the case/shoulder junction, the fired brass is .006” larger than factory.
This “first stretch” factor may also support the “fireform before you tune” argument.

I would agree that the first firing should see the greatest increase, but I am still wondering if the case fully forms to the chamber on the first firing, and simply springs back less with each successive firing, as the case work hardens. So the volume while firing may not actually increase with each firing. Since we can't measure the case dimensions at maximum pressure, we will never know.

[Pathfinder76]

Originally Posted by 260 Rem

FALLAIRFEVER - if I was starting over again, I would buy a single Redding Type S FL die (with bushings) for resizing, and a Wilson in-line seater to seat bullets.

This is good advice. I use Type S FL dies and Forster seaters

[BrodyGil]

Personally I stopped neck sizing and started to FL but only bumping the shoulder back .002”. This has helped eliminate tight bolt closes and I haven’t notice a difference in velocity or accuracy with my 260rem and 300WM. I also anneal after every firing.

[DLab]

Originally Posted by 260 Rem

FALLAIRFEVER - if I was starting over again, I would buy a single Redding Type S FL die (with bushings) for resizing, and a Wilson in-line seater to seat bullets.

Yup,Redding type S bushing FL sizers ,Wilson or Forster seaters . Redding body die and Wilson bushing neck sizer work well combined .
These are my preference brands for dies ,Whidden dies are also excellent.
Most of these can be a little pricey though ,IMO the Hornady dies are good value for a person just starting out reloading for standard hunting calibers.

[lclund1946]

Originally Posted by 260 Rem

Only measuring can answer definitively, but by best guess is the biggest “stretch” occurs on first firing. On my 11x fired brass...after I FL sized, at the case/shoulder junction, the fired brass is .006” larger than factory.
This “first stretch” factor may also support the “fireform before you tune” argument.

Elasticity is defined as:
1. the ability of an object or material to resume its normal shape after being stretched or compressed; stretchiness, springiness.
2. the ability of something to change and adapt; adaptability.

If the pressure is low enough that the brass is not stretched beyond its elasticity it will return to its original shape. This is what I was pointing out with this LC REF brass shot with a load that pushed a 40 V-Max at over 3600 fps in my 20 EXTREME. Pressure was just enough to seal the neck (about 0.004" with 0.0015" spring back from the chamber) and expand the brass about 0.001" at the shoulder or 0.002" with 0.001 springback) as there is 0.002" clearance. As the brass did not expand at the base my FL dies which size to 0.3732", at that point did not touch the brass. The brass was not sized at the shoulder diameter as the die sizes 0.001" over new LC brass and the same under the chamber. As the shoulder did not move only the neck is sized back to its original size so the brass never really stretches. This is where the first accuracy node is found by running a pressure ladder

New brass 0.3732" base diameter :
[IMG][/IMG]

Fired brass 0.3732 base diameter:
[IMG][/IMG]

Fired Brass and Newly formed brass at just over trim length:
[IMG][/IMG]

If you develop loads this way, by only stretching the brass to match FL dies and setting the dies to form the brass to fit the chamber with minimum HS, you can create the same situation using FL sizing.

If I run the pressures up until the brass conformed to the chamber, with minimal springback, then the dies would have to work the brass, at the base and shoulder, by 0.001". The shoulder remains in the same position and the brass is forced forward along the shoulder/neck and up along the neck where it will eventually have to be trimmed. If you got a custom die cut to match your chamber like this you would have the same situation. Of course you could also Neck size, as you do, until the brass becomes work hardened and will not get any springback they you will have a sticky bolt.

Likely a better way to go if you want to Neck Size, and likely what most people do, is fireform to Max Saami Cartridge Specifications. You will need to run pressures that will be getting 0.001" springback from a Saami Minimum chamber or 0.003" from a Saami maximum chamber.

Here is a link to a Saami drawing showing Maximum Cartridge and Minimum Chamber dimensions for a 308 Win.. Not there is only 0.001" difference at the 0.200 Datum/Shoulder and Neck diameters. Diameter tolerance from Minimum chamber to Maximum chamber is 0.002". Case diameter tolerances can be as much as Minus 0.008" so new brass can really stretch a lot if it is at minimum tolerance. Saami chamber all have to be cut to these specifications so the only "sloppy Saami Chamber" is likely one cut to maximum tolerances running minimum tolerance brass. Thankfully manufacturers are tightening up these tolerances, especially with the new cartridge designs, almost to the point that wildcatters won't have anything to 'Improve On".

http://www.saami.org/PubResources/_C...Winchester.pdf

I will be adding information illustrating some of this as I get tests completed. I can say that none of the Factory 223 and 270 Winchester brass stretched more than the FL die measurements at the base datum. I was lucky enough to get some samples of new 223 brass, head stamped Dakota and IMI, to add to my test.

[HW223]

Originally Posted by lclund1946

Elasticity is defined as:
1. the ability of an object or material to resume its normal shape after being stretched or compressed; stretchiness, springiness.
2. the ability of something to change and adapt; adaptability.

If the pressure is low enough that the brass is not stretched beyond its elasticity it will return to its original shape. This is what I was pointing out with this LC REF brass shot with a load that pushed a 40 V-Max at over 3600 fps in my 20 EXTREME. Pressure was just enough to seal the neck (about 0.004" with 0.0015" spring back from the chamber) and expand the brass about 0.001" at the shoulder or 0.002" with 0.001 springback) as there is 0.002" clearance. As the brass did not expand at the base my FL dies which size to 0.3732", at that point did not touch the brass. The brass was not sized at the shoulder diameter as the die sizes 0.001" over new LC brass and the same under the chamber. As the shoulder did not move only the neck is sized back to its original size so the brass never really stretches. This is where the first accuracy node is found by running a pressure ladder

New brass 0.3732" base diameter :
[IMG][/IMG]

Fired brass 0.3732 base diameter:
[IMG][/IMG]

Fired Brass and Newly formed brass at just over trim length:
[IMG][/IMG]

If you develop loads this way, by only stretching the brass to match FL dies and setting the dies to form the brass to fit the chamber with minimum HS, you can create the same situation using FL sizing.

If I run the pressures up until the brass conformed to the chamber, with minimal springback, then the dies would have to work the brass, at the base and shoulder, by 0.001". The shoulder remains in the same position and the brass is forced forward along the shoulder/neck and up along the neck where it will eventually have to be trimmed. If you got a custom die cut to match your chamber like this you would have the same situation. Of course you could also Neck size, as you do, until the brass becomes work hardened and will not get any springback they you will have a sticky bolt.

Likely a better way to go if you want to Neck Size, and likely what most people do, is fireform to Max Saami Cartridge Specifications. You will need to run pressures that will be getting 0.001" springback from a Saami Minimum chamber or 0.003" from a Saami maximum chamber.

Here is a link to a Saami drawing showing Maximum Cartridge and Minimum Chamber dimensions for a 308 Win.. Not there is only 0.001" difference at the 0.200 Datum/Shoulder and Neck diameters. Diameter tolerance from Minimum chamber to Maximum chamber is 0.002". Case diameter tolerances can be as much as Minus 0.008" so new brass can really stretch a lot if it is at minimum tolerance. Saami chamber all have to be cut to these specifications so the only "sloppy Saami Chamber" is likely one cut to maximum tolerances running minimum tolerance brass. Thankfully manufacturers are tightening up these tolerances, especially with the new cartridge designs, almost to the point that wildcatters won't have anything to 'Improve On".

http://www.saami.org/PubResources/_C...Winchester.pdf

I will be adding information illustrating some of this as I get tests completed. I can say that none of the Factory 223 and 270 Winchester brass stretched more than the FL die measurements at the base datum. I was lucky enough to get some samples of new 223 brass, head stamped Dakota and IMI, to add to my test.

This is a long way around a simple enough issue , if the sizing die fits the chamber, measure the fired brass at the top of the case body just under the shoulder with a vernier and lock it ,size it , put the vernier back on the brass , if it drops down the body more than 1 blade width to 1 1/2 blades widths max , it’s over sizing and you are effectively fire forming every time you size it ,the shoulder should be set back enough that there is slightest drag when the bolt handle is 3/4’s of the way closed with the cocking piece removed,( roughly .001-.0015 ) , if it’s not dropping any ,your not sizing enough and it will get tight at some point , Check it at the bottom of the body as well ,If you can’t adjust your die to get in this area ,the die does not fit your chamber ,replace it ,no amount of messing around will fix it.
We run a lot of pressure in most of our rifles most of the time ,after roughly ten firings we check them and will typicallly have almost no lengthening issues .0003-5 with most lots of brass ,
There are some times when we run the lower node to us which is still way over “Sammi”. If the sizing die is a proper fit the brass does not seem to grow or loose elasticity at all, no need for drawings or theoreticals , ask the Gun ,it’s what matters in the real world .
We don’t neck size because even though you can’t feel it initially the brass is changing , hence the reason to fl size every so many firings, if your not trying to squease every last bit out of it and it’s not giving you trouble this is fine.
It’s very important to get a sizing die that fits the chamber ,with out that brass issues will never go away .

[lclund1946]

Originally Posted by HW223

This is a long way around a simple enough issue , if the sizing die fits the chamber, measure the fired brass at the top of the case body just under the shoulder with a vernier and lock it ,size it , put the vernier back on the brass , if it drops down the body more than 1 blade width to 1 1/2 blades widths max , it’s over sizing and you are effectively fire forming every time you size it ,the shoulder should be set back enough that there is slightest drag when the bolt handle is 3/4’s of the way closed with the cocking piece removed,( roughly .001-.0015 ) , if it’s not dropping any ,your not sizing enough and it will get tight at some point , Check it at the bottom of the body as well ,If you can’t adjust your die to get in this area ,the die does not fit your chamber ,replace it ,no amount of messing around will fix it.
We run a lot of pressure in most of our rifles most of the time ,after roughly ten firings we check them and will typicallly have almost no lengthening issues .0003-5 with most lots of brass ,
There are some times when we run the lower node to us which is still way over “Sammi”. If the sizing die is a proper fit the brass does not seem to grow or loose elasticity at all, no need for drawings or theoreticals , ask the Gun ,it’s what matters in the real world .
We don’t neck size because even though you can’t feel it initially the brass is changing , hence the reason to fl size every so many firings, if your not trying to squease every last bit out of it and it’s not giving you trouble this is fine.
It’s very important to get a sizing die that fits the chamber ,with out that brass issues will never go away .

I have been trying to explain how the average hunter/shooter can either NS or FL size and develop good safe loads without custom dies cut to match the chamber with minimal clearance. When you say "we" I assume that you are referring to short range BR shooters who typically only run 6mm PPC which is a "Wildcat Cartridge". This is much different than what we are discussing as you fire form brass to fit the chamber and dies are cut to FL size the brass with minimal tolerance. I do it a bit different in that I have custom dies made to form new brass that fits the chamber, as you outlined while maintaining its original dimensions from the shoulder down, and a chamber cut to match the brass with minimal tolerance. The result is the same except in my design brass is not stretched past its elasticity, at the base datum and only 0.001"- 0.002" at the shoulder, when fired at the low pressure node which is likely below Saami.

I was trying to point out that one could do the same by running Saami pressures and not stretching the New brass past the dimensions of the vast majority of FL dies. One cannot do this by running pressures needed to fireform new brass to the Saami chamber as the Saami drawings show when compared to a new brass. However, as I pointed out, I have not found any factory 223 or 270 Winchester loads that stretch brass past the FL die dimensions at the 0.200" datum. That is what happens "in the real world" and can be proven to ones self if one takes the time to look at the drawings and take measurements as I do.

I took on the task of finding a load for a friends 270 Win with the 150 LRAB bullet and IMR7977 . The Hornady Manual showed a Max Load as 60.9 grains, Compressed) getting 2940 at 61,000 PSI. A quick check of the Saami drawing told me that the 270 Win had ZERO FB which surprised me as measurements showed I could not get anywhere the lands with the 150 AB.. When I looked at the Throat Angle and found it to be 0 degrees 47' 33" I knew why. I also determined that the Saami Minimum chamber measured 0.470" at the base datum and the Max Cartridge dimension was 0.4698". FL sizing a Winchester Fire formed brass I determined that the RCBS die sized the base datum to
0.4686" or about 0.001" below Max cartridge which is perfect. The die did not overwork the neck so I was good to go as I had set the die to form the brass with the proper HS.

Sa you can see, by the following chart, even the 2X Fired NS Winchester brass had not fireformed to the Saami Mimimum chamber. Even Hornady Superformance 140 SST @ 3023 did not fireform brass to the FL die at the base datum. In fact it had 0.4641" clearance as per my measurements, Needless to say this brass was a perfect candidate to Develop a FL sized load with this bullet powder combination. I had a whole lot of Federal brass that I had annealed and FL sized but realized that it did not have enough capacity, even NSized, to get the velocity I was hoping for. Winchester NS brass held the same amount of powder as the Hornady FL brass so it was one of the two. Hornady brass won out as about 60.8, slightly compressed, gave me the pressure spike and best load I was looking for at about 2875.

[IMG][/IMG]

This drawing got me on the right path and I let the gun decide which path it preferred with the components I chose. I wound up with a good safe load, well within Saami Limits, without loading to stiff bolt. My friend is very happy with that load and the brass will last for many firings. If I was to use his Federal brass I would have to go with a faster burning powder like H 4831and would likely find a good load at similar pressure but slightly less Velocity.

[IMG][/IMG]

[HW223]

.223 , 22 ppc , 220 swift ,6 br , 22br ,6x233,6x47 Lapua , 6.5x47 lapua,6.5x06,6.5x284,25-06, 30-06,300 win mag , 338 win mag , 338 lapua mag ,
All done the same way , why would I put up with a die that does not fit the chamber even on a factory chamber ?
Same rules for all , ask the Gun what it wants not the other way around

[6MT]

Originally Posted by FallAirFever

Couple questions, who makes bushing dies and what do they do? Do they neck and bump the shoulder as well?

Whidden. Yes.

[lclund1946]

Originally Posted by 260 Rem

Just for interest this AM, I used some H380 to compare fill volumes ... on a piece of 11X fired 6.5 X 47L (NK sized only), I NK sized, installed a new primer, filled to capacity with 20 “taps” to settle powder. Then, FL sized with a Redding body die, same fill technique.
Difference in volume by weight was 0.6 grains less in FL resize case.

Here is the fill technique I use with Ramshot X-Terminator to compare case capacities. I do not tap or use a drop tube as I believe pouring into the Hodgdon Snap Spout gets the powder evenly into the funnel the same every time. I did three new 223 Remington cases with the Dakota on left with 30.8 grains, IMI center with 30.6 grains and a Winchester holding 30.7 grins on right. I checked 4 more of each and they all held the same.
[IMG][/IMG]

[Pathfinder76]

You can overthink this till the cows come home.

[Pathfinder76]

Originally Posted by lclund1946

Here is the fill technique I use with Ramshot X-Terminator to compare case capacities. I do not tap or use a drop tube as I believe pouring into the Hodgdon Snap Spout gets the powder evenly into the funnel the same every time. I did three new 223 Remington cases with the Dakota on left with 30.8 grains, IMI center with 30.6 grains and a Winchester holding 30.7 grins on right. I checked 4 more of each and they all held the same.
[IMG][/IMG]

Case capacity should be measured to the neck/shoulder junction.

[Ryan.M.Anderson]

In the PRS match shooting world neck sizing is very rare.

When you are on the clock you do not want a piece of brass to not chamber and you don't want a hard to chamber piece of brass either as the force to close the bolt can make you more unstable.

I use a normal FL die with the expander button removed and then expand the neck using a mandrel.

I do all my brass prep on a Dillon now so it doesn't take too long to perform both steps.

[Pathfinder76]

Originally Posted by Ryan.M.Anderson

In the PRS match shooting world neck sizing is very rare.

When you are on the clock you do not want a piece of brass to not chamber and you don't want a hard to chamber piece of brass either as the force to close the bolt can make you more unstable.

I use a normal FL die with the expander button removed and then expand the neck using a mandrel.

I do all my brass prep on a Dillon now so it doesn't take too long to perform both steps.

This would also be an exceptional way to size cases. How do you determine mandrel size?

[Pathfinder76]

A good read.

http://m.tecomate.com/?url=http%3A%2...referrer=#2931

[DLab]

Mandrel dies for neck turning typically come with an expander and turning mandrel ,the expander is usually 0.001 larger than the turning mandrel.
My 21st. century made 30 cal. mandrels measure E-0.3060 -T-0.3050,.264 mandrels are E- 0.262 T- 0.261 ,so you have two diameter neck sizes to use for sizing necks ,adjust bushing size to match for required or preferred neck tension .I don't have gauge pins to use ,but I anneal every third firing at most to try to control work hardening. When I turn necks I just touch the shoulder at the neck/shoulder junction with a 30 degree cutter to help control brass growth migrating into neck area .I check neck wall thickness every 2/3 firings.
To size my 30br. brass from 6 Br. Lapua I had to get a larger diameter expander mandrel from PMA Tools ,due to the spring back and donut formed at base of neck, this is a known problem and required an expander of 0.3070 ,specifically made to deal with the issue .
Manufacturers will custom size to order if need be.
Running new brass over the mandrels to make sure necks are concentric and lessen the usual typical excessive neck tension of new brass is another use for mandrels.

[lclund1946]

Originally Posted by chuck

Case capacity should be measured to the neck/shoulder junction.

To coin one of your favorite reply's Chuck. Why?

[Pathfinder76]

Originally Posted by lclund1946

To coin one of your favorite reply's Chuck. Why?

That is standard practice. I assume it is because you have a bullet in the neck to varying degrees and therefore to have some semblance of consistency they do that.