I was just wondering how many people use neck sizing dies versus using a Full Length resizing die that you have set to only partially resize.

I've often heard that neck sizing dies were a waste of money, but thus far the 4 rifles I have bought neck sizing dies for shoot more accurately at 300 yards with neck sized cases than partially resized cases. The most considerable difference has come from my .300 Winchester Magnum. Has anyone else seen an improvement going to a neck sizing die versus a FL resizer set to partially resize?

I use neck sizers for all of my "serious" reloading. Anything that will be used in my 40-X, or for long range groundhogs, or single shot competition, gets neck-sized.

For all of my big game hunting stuff, I use full length sizers.

I've experimented with partial resizing, but just went ahead and bought neck sizers for the few calibers that I try to wring the last little bit out of. They're not all that much money when you consider how much other "money" is laying on my reloading bench, and I know the results are going to be good...

ONE IN THE SAME,I think you gain in the brass lasting longer.
develope a load either way thats accurate in the rifle your using

I use neck size dies where available.

Uh oh, Hot Core will be around shortly I'm sure. He and I have had this "discussion" for at least 4 years that I remember, maybe longer.

I do both but I prefer neck sizing and that's where I get my best accuracy in most cartridges. There are a couple of wildcats for which there were no neck sizing dies available and I PFL there. In only one instance did PFL clearly prevail for accuracy and I later discovered the neck sizing die which was expanded from a smaller caliber, was introducing runout into the neck sizing operation.

If you don't have the money or don't want to spend it on a neck die I think PFL sizing is "almost" as good, but it also depends on how your die and chamber mate up. If you have to size a neck way down as in many factory chambers, then possibly PFL sizing may be of benefit. If the chamber is reasonalbly close in that area I think neck sizing is preferable.

I use Lee Collet dies to NS where ever I can get them, except for a few calibers where I prefer the Redding Bushing Competition Neck dies. The preferred FL die is a Redding Body die - used when needed to bump shoulders etc.

- mike

Neck sizing dies almost exclusively from .22 Hornet to .300 RUM.

I use a combination of Redding Bushing Dies or RCBS Dies that I had JLC convert to Bushing Dies.

All of my applications are for hunting.

I use NS dies on all my bolt action cartridges. If they are used for hunting they all get cycled before loading. All my lever action get full length resized.

Hey Buzz, Yes Bob338 is correct about us having discussed this for a long time.

Let me first say, that if Neck Sizing provides better accuracy for you(or anyone else) then for sure you(and those folks) should use it. However, All cartridges should be Full Length Resized in Dangerous Game country.

If you will run a "Blind Test" on P-FLR vs Neck Sizing, your results might just surprise you though. Just load some up both ways and let a buddy hand them to you without telling you which ones you are getting. I like 15-18 shots on a single target for each type when I do this.

The dynamics of the P-FLRed case simply causes the "Case centerLine" to be forced into alignment with the "Chamber centerLine". This in turn causes the Bullet to start forward into the Lead completely straight.

The neck Sized cases just lay on the bottom of the chamber. And since the centerLines are off-set slightly, it should not be a surprise to anyone that the Bullet just won't enter the Lead as straight as the P-FLRed version.

That said, I'll go back to my original statement and recommend that you use whatever method provides the best accuracy for you.

You can't have "too much" accuracy!

quote:

---

Originally posted by Hot Core:
The dynamics of the P-FLRed case simply causes the "Case centerLine" to be forced into alignment with the "Chamber centerLine". This in turn causes the Bullet to start forward into the Lead completely straight.

The neck Sized cases just lay on the bottom of the chamber. And since the centerLines are off-set slightly, it should not be a surprise to anyone that the Bullet just won't enter the Lead as straight as the P-FLRed version.
_

---

Hot Core,
Could you please explain the dynamics whereby the fireformed case to chamber relationship is maintained by partial full length resizing, but is desroyed by neck sizing only.

I'd like to understand that as well. In both cases the shoulder isn't set back. Both may require slight force in closing the bolt. That bit of force insures the case is a "glove fit". In the case of a PFL case, that little bump at the base of the neck centers the case. The ENTIRE case is centered in the neck sized case!

That's where Hot Core and I diverge. I see more problems with the PFL case having the body at the shoulder reduced where in the neck sized case it stays the same.

Idaho Shooter, trust me, you'll never convince Hot Core. I've tried to see his point for many years and while I highly respect his knowledge and reloading ability, this is one where we part ways. I've never convinced him and he'll never convince me. Like religion for someone you consider a friend, you just don't discuss it with them.

That's all I use, but every now and then I run a few cases through the full size die. I mostly do that with new cases, since I have no idea if the factory has made an error during the manufacturing process. Once I fire the round, I only neck size to the dimensions of a fired once or twice case.

I have become hooked on the bushing dies and the control they offer in neck tension and concentricity. Currently loading about 8 different caliber with this method. I won't be going back to the other methods.

I dont know what hot core is refering to either, Unless he is refering to a Bad chamber that is out of round or offset. How is a neck sized case going to just lay on the bottom of the chamber? Its fire formed to the chamber and will be snug fit on the sides.

I`m not sure I follow HC either. The fire formed case should be a thousanth or so smaller then the chamber and yes it will "lay" on the chamber bottom and the bullet/neck centerline (runout) will be toward the lower part of the bore. The partial sized case will be even smaller in diameter at the shoulder as you`re not sizeing the base (never do with any sizeing) and the case center line will fall even lower in the bore. Bumping the shoulder will add more to the possible angle of the bullet to the bore as the shoulder helps aline the case when the bolt presses it tight against the front of the chamber.
At any rate I prefer to neck size, more because I don`t lube cases sized this way and do when I part size. Just plain laziness on my part

quote:

---

Originally posted by Idaho Shooter:

quote:

---

Originally posted by Hot Core:
The dynamics of the P-FLRed case simply causes the "Case centerLine" to be forced into alignment with the "Chamber centerLine". This in turn causes the Bullet to start forward into the Lead completely straight.

The neck Sized cases just lay on the bottom of the chamber. And since the centerLines are off-set slightly, it should not be a surprise to anyone that the Bullet just won't enter the Lead as straight as the P-FLRed version.
_

---

Hot Core,
Could you please explain the dynamics whereby the fireformed case to chamber relationship is maintained by partial full length resizing, but is desroyed by neck sizing only.

---

Hey Idaho Shooter, First let me correct one thing you said. You "implied" that I said the case to chamber relationship is "destroyed by Neck Sizing". Obviously you have been studying under denton's method of "skewing posts". I didn't say that.

Here is how P-FLR works:

On P-FLR, the case is held in compression between the Bolt Face and Chamber Shoulder. The Case Walls do not touch the Chamber Walls. The flat Case Head and the tapered, conical Case Shoulder are the two points of contact and are under a slight compression. The amount of compression is controlled by the way the Full Length Seating Die is adjusted.

Due to the Case being held in compression between those two points, the Case centrLine and the Chamber centerLine are in almost perfect alignment.

If anyone needs more on that, let me know.

Now, concerning the Neck Sizing Dies:

Starting with a "new" case, it is fired and the case expands to fully fill the chamber, then contracts slightly in all directions. The Case is now slightly loose in the chamber and laying on the bottom.

When the case is NSed, only the Neck is reformed, nothing is done to the Case Walls nor the Shoulder. So, when the Case is reloaded and placed in the chamber, it continues to lay on the bottom. Nothing on the Case is held in compression with the chamber.

Firing continues with NSing and the case continues to expand and contract, however the contractions become less and less with each firing. (The centerLine of the Case is getting closer to the Chamber centerLine.)

At some point the NSed Case needs the "Shoulder bumped back" so the case will still go into the chamber with the normal NSed lack of effort.

At this point(before the Shoulder Bump), the NSed case has the greatest "potential" to be accurate, because it is now in compression between the Bolt Face and Chamber Shoulder(the centerLines are now in alignment) - just like the P-FLRed case is held for each shot.

But, the people who NS now "Bump the shoulder back" which creates the non-compressed fit in the chamber(aka loose fit) and the case is once again laying on the bottom of the chamber. At this point, you have less of a "potential" for great accuracy.

---

That is how it works for both P-FLR and NS. If it is still unclear, let me know.

But, as I said in my original post, if NSing works best for you, by all means use it. Especially if you happen to be shooting against me to see who buys the BBQ for supper.

I have always used partial resizing for all cases fired in the rifle that they will be used in again next time, except for a Ruger 1V .25/'06 I once was trying to get maximum accuracy from. I used Forster benchrest dies with this rifle, and bought a neck-only sizer for the set. The idea was to see if the rifle could be made to shoot better with cases sized neck-only. The answer was NO! It didn't make any difference at all.

I neck size only using the Lee collet die because it produces really straight ammo, it works the neck less and because it's so damn easy to use since you don't have to lube your cases. I use Redding body dies to size the body when necessary.

I use PFLR only;no luck with the neck sizer...

HC, so if you start with a NEW case and fire it,..then PFL it,..doesn't it expand and contract the same as the NK sized case,..therefore creating the same body dimension? and if so,..then if my bushing NK dies only size 3/4 of the neck and do not touch the shoulder,..don't I still have the compressed fit from shoulder to casehead? My NK dies don't bump shoulders,..that is the whole point in NK sizing from my understanding. I do not run ANY die down to the shellholder,..so PFL and NK sizing are almost identical operations on my bench.

JustC I dont know where HC got his theory .Documented tests writen in some book or if just in his mind or if it actually has credibility.

Some cases if you neck size with a FL die they may touch and push in the case sides alittle which may create a longer length from the head to the shoulder, Or the neck size expander button may pull the case longer.
Some caliber cases that have alot of tapper, neck sizeing with a Fl die wont even touch the case sides, Just like you stated.

My one and only experiment with NS'ing led to enormous headaches with runout.

PFL sizing has worked very well for me...hunting rifles only.

YMMV!

quote:

---

Originally posted by JustC:
HC, so if you start with a NEW case and fire it,..then PFL it,..doesn't it expand and contract the same as the NK sized case,..therefore creating the same body dimension?

---

Hey Just C, Good question. Yes that is correct in that they both expand to fill the chamber and both contract.

quote:

---

and if so,..then if my bushing NK dies only size 3/4 of the neck and do not touch the shoulder,..don't I still have the compressed fit from shoulder to casehead?

---

No.

The significant difference between the two methods comes from the Full Length Die "resizing" the Pressure Ring and Case walls back close to SAAMI Spec. When this happens, it causes the Case shoulder to move slightly forward.

An example might help clear it up a bit. And the good thing is you can do this on your own rifle and Dies to verify it. Let's say you are using good old RCBS or Redding "Standard Die Sets" for a cartridge in a Bolt Action rifle.

1. Screw the FL Die into the press so the bottom of it stops about the thickness of a nickle above the Shell Holder.

2. Lube a fired case, resize it and wipe the lube off.

3. Insert the case in the chamber and close the bolt.

You should feel the bolt close with the exact same amount of resistance as if no case was in the chamber.

4. Screw the FL Die into the press 1/8th turn and repeat #2 & #3 above until you begin to feel the bolt close on the case with a bit of resistance.

You are really close to where you want it set, so go from 1/8th turns, to 1/16th or 1/32nd.

5. As you continue, at some point you may not be able to close the bolt. That means the case walls are resized and the shoulder has extended forward.

6. Screw the FL Die in just a bit further and the Die begins pushing the Case-Shoulder back slightly.

All of a sudden you will be able to close the bolt with a slight bit of resistance. You are now at the perfect P-FLR and the chamber has "Zero headspace".

7. Now you need to adjust the FL Die Lock Ring so the Die can return to this same position in the press. A bit of fine tuning may be needed, but that is how you get there.

8. Going just a bit farther in with the FL Die will allow the bolt to close on the case with "no resistance" once again. Here you are Full Length Resizing and this should be done for all cartridges used where you will be in the proximity of Dangerous Game.

[/quote]My NK dies don't bump shoulders,..that is the whole point in NK sizing from my understanding. ...[/QUOTE]I agree.

At some point though, if you are using Loads approaching a SAFE MAX, you will eventually get to the point where you will need to "Bump the Shoulder Back" so you can close the bolt. If you have not reached this point, it is just a matter of time.

Best of luck to you.

quote:

---

Originally posted by GSP7(in his first post):
I dont know ...

---

quote:

---

Originally posted by GSP7(in his second post):
JustC I dont know ...

---

Must admit those are the first pieces of your posts I've been able to agree with in a long time. Good to see you stating the obvious.

quote:

---

Originally posted by CDH:
My one and only experiment with NS'ing led to enormous headaches with runout...

---

Hey CDH, Very interesting you should bring up "runout". This is one of the things that Bob338 and I discuss during our talks about the P-FLR vs NSing.

I see all kinds of folks nearly driving themselves crazy trying to get "runout" under control. I believe it was "bigcountry" who had such a hassle with it last year. And it seems they are generally Neck Sizing when they have such runout issues.

Have you tried measuring the runout on your P-FLRed cases just to see how far out they are? And then shooting some groups?

I've never even bothered with it, cause my rifles and loads typically shoot well enough that it isn't even a concern for me.

---

For what it is worth, it may have been "Knobmtn" or one of the other Benchrest folks that mentioned they are seeing a trend toward P-FLRing instead of NSing among other Benchresters. No doubt they are looking for every accuracy advantage they can get. And from what I've seen over the years, it is obvious which method is the best for "my best accuracy".

But, the very best thing about this, is everyone can go out and prove it to themselves by just running the "Blind Test".

Best of luck to you folks.

Hotcore , Are you insecure ,you act like a child

HC,..so if I seat for single feeding with a 0 clearance or even a +.002" into the rifling,..won't that bullet's contact with the lands help to square the round up by stabilizing the ogive in the throat while simlutaneaously providing rearward pressure to the boltface?

How many firings before a case hardens enough to rely on bushing NK sizing to provide this same effect?

Hotcore,
I understand the theory, but I think I need X-rays to provide the "proof"

Hot Core;holds on,PFLR against the neck sizing,very interesting topic,I use PFLR on both rifles I owe,why,I cannot get fine accuracy with the neck sizers.Took me five years to get that particular .30-378 WBY shooting fine,the neck sizing thing didnt do any good accuracy with RCBS neck die;(REDDING the same thing). I finally find fine accuracy with the FORSTER bench dies,the full sizer works fine,smooth full sizing.AFter 5 years reloading this caliber,I will stick with the PFLR.The other caliber is the .338RUM,Forster dont make the dies for it...

Looks like I may have dug up a previous pissin match

Not realy,,HotCore is always Pissin his pants

quote:

---

Originally posted by JustC:
HC,..so if I seat for single feeding with a 0 clearance or even a +.002" into the rifling,..won't that bullet's contact with the lands help to square the round up by stabilizing the ogive in the throat while simlutaneaously providing rearward pressure to the boltface?

---

Hey JustC, I'd actually started addressing that exact thing in my last post to you and went back and erased it.

What I was going to say, was that NSers who Seat into the Lands "might" get some benefit from it. But, it seems the "runout" issue common to the NSing tends to negate some of that benefit.

If you do not have access to Full Length Dies, it would always be an interesting Test to try NSing and Seating-into-the-Lands to see if it increases accuracy for you. It might or might not.

If you try it, it would be best to work back up to your current level. Seating into the Lands has the potential to change the Peak Pressure point slightly during the firing sequence and thus the barrel harmonics. So, it might help or hinder accuracy and not give you a true indication about helping you or not.

Just went to look at my notes from the last time I compared P-FLR to NSing and I had the bullets Seated 0.010" Into-the-Lands with both sets of cases. In my Test, the P-FLRed cases still edged the NSed cases. But, it might work just fine for you.

quote:

---

How many firings before a case hardens enough to rely on bushing NK sizing to provide this same effect?

---

No way to give you a good answer because it is dependant on multiple variables:
1. Case Lots are all annealed when we get them, but not the same between manufacturers.
2. If your Loads are relatively mild, they will not expand the case as much during firing and the shoulder will not "creep forward" as quickly as hotter loads.
3. If the Expander Ball is "dragging" heavily on the inside of the Case neck, it can pull the shoulder forward slightly.

If I left any out, anyone that sees one, pleas include it.

quote:

---

Originally posted by Idaho Shooter:
Hotcore,
I understand the theory, but I think I need X-rays to provide the "proof"

---

Hey Idaho Shooter, Do not take this as a slam on you cause it is not intended as such. It is more difficult for some people to mentally visualize what is going on in mechanical fit situations than some other people. Even some of the Mechanical Engineers I've worked with over the years would have(costly) lapses from time to time.

I generally was assigned to the Rejected Material disposition team. One of my favorite write-ups was, "Won't fit because it meets the print!" Meaning the supplier had provided exactly what the Design Engineers had requested, but it wouldn't fit with the mating part(s).

As for me, the relationship between the P-FLRed case and the chamber is very clear. When you get the X-rays, provide a link so we can all see that I was - RIGHT AGAIN!

quote:

---

Originally posted by Buzz:
Looks like I may have dug up a previous pissin match

---

Hey Buzz, I can't remember when it started with GSP7. Maybe discussing (rag) Pre-64 M70s or the excellent M700s.

As everyone can clearly see, he can hand it out much much better than he can take it.

Hey rejpelly, Sounds like you went through a considerable amount of effort to give NSing a fair chance. Glad to hear you got the accuracy you wanted with P-FLRing.

New to this forum, but what you are saying makes a lot of sense Hot Core. It would be informing if GSP 7 would take the time to explain neck sizing in as great a detail as you have explained your theories and not resort to insults.

Will try your test. The latest I've been doing is using a sized case with the best concentricity ( .001" ) and screwing the FL die onto the case in order to straighten the die in the press before sizing the rest of the cases. Does this work or do you have a better method for maximizing concentricity? Using a rubber washer under the decapping pin lock nut also, to try to float the expander ball so it doesn't pull the neck from side to side as much.

I quit neck sizing because I didn't like the resistance to chambering I was getting.

quote:

---

An example might help clear it up a bit. And the good thing is you can do this on your own rifle and Dies to verify it. Let's say you are using good old RCBS or Redding "Standard Die Sets" for a cartridge in a Bolt Action rifle.

1. Screw the FL Die into the press so the bottom of it stops about the thickness of a nickle above the Shell Holder.

2. Lube a fired case, resize it and wipe the lube off.

3. Insert the case in the chamber and close the bolt.

You should feel the bolt close with the exact same amount of resistance as if no case was in the chamber.

4. Screw the FL Die into the press 1/8th turn and repeat #2 & #3 above until you begin to feel the bolt close on the case with a bit of resistance.

You are really close to where you want it set, so go from 1/8th turns, to 1/16th or 1/32nd.

5. As you continue, at some point you may not be able to close the bolt. That means the case walls are resized and the shoulder has extended forward.

6. Screw the FL Die in just a bit further and the Die begins pushing the Case-Shoulder back slightly.

All of a sudden you will be able to close the bolt with a slight bit of resistance. You are now at the perfect P-FLR and the chamber has "Zero headspace".

---

HC isn`t this acually the proper method of die adjustment and not partial sizeing? I`ve always been told the die should just "touch" the shoulder when the sizer was properly adjusted for FL sizeing. The FL sizer usually won`t touch the shoulder, let alone set it back, until the die hits the shell holder in most of my Redding, RCBS and Forster FL dies. You need the press to cam over to reduce headspace in most of them. I might have just the right chamber/die relationships for this to occur but with 9 different chamberings I kinda doubt it is not the norm.
Partial sizeing should not touch the shoulder and the die should only hit the body enought to insure straight feed of the case in the die. The neck WON`T be full sized, the sizeing will end before the should/neck junction, same as a NS die will. Tapered cases(`06, 300H&H mag, ect) may not have enought expanded body to even hit the die wall.
The point of the shoulder hitting the forward chamber and centering is valid. The bullet in the rifleing is another way of doing the same. The BR shooters use the bullet jammed as it not only seats the cartridge square but improves on igition makeing for more uniform velocity. The resistance of the bullet provides more uniform tension then a snug neck or crimp will.It also almost guarentees you`ll pull the bullet if you have to open your action without fireing it.

Woods,
The easiest way to square your die in the press is to put a flat washer or other flat/even spacer on the shell holder and raise the ram to apply pressure on the bottom of the die. A feeler gage will work to give measured space if you want. There are also shellholders that come in varying heights that allow you to square your die on them and leave a bit of HS adjustment.

Thanks for your reply Ol` Joe

What I am trying to correct by screwing the die down on a concentric case is to square the side to side movement of the die in the press. Perhaps it is my old RCBS press, but when I am threading a die into the press there is some play in the threads and I can move the top of the die back and forth before I lock nut it down. Seems to me that if you screw it down with the shell holder or washer/shell holder in the up position, you are assuming that the shell holder or washer/shell holder is a perfectly flat horizontal surface and that the bottom of the die is perfectly horizontal to the vertical of the die. Even a 1/1000" difference might make 5/1000" off vertical change up at the neck. A washer or feeler gauge would work to keep from full length sizing but not the problem of alignment of case body and neck.

Might be splitting hairs but since I've started doing it my way, I have noticed an decrease in sized shell concentricity from an average of .003 to .0015 or less. Of coarse it needs to be combined with neck turning, annealing, etc.

I raise the fired and hopefully now straight case, into the die with the lock ring loose,..then as the case has straightened the die body,..I lock the ring. Now,..as the expander ball (if using one) just enters the neck on it's way back out,..that will center the expander in the straight fireformed neck,.at which point while maintaining tension,..I lock the ring on the decapping assembly. That should give you a pretty straight die set-up. MHO

Guys I need help for a F/L dies set for the.338RUM.Forster cannot make their bench rest dies for it(what I like about Forster F/L dies set is"smooth resizing" compare to LEE and RCBS having"hard resizing"(causing problem with uniformity on the body of cases,area below the shoulder .5"or so.I consider two new choices;Z-Hat FL custom dies(cost a lot),I dont know anthing about the accuracy of their dies.Next one is Redding:type S match full die set.Is their F/L sizer sizing "smoothly" or sizing as LEE or RCBS.F/L sizing with RCBS the diameter of the case is without bullet.363".bulet inside.365"(factory load.365").How to choose the correct bushing between.362-.365...