Neck Sizing VS Full Length Resizing

[bwframe]

I just started reloading rifle cartridges. I have a fair understanding, having loaded handgun cartridges for numerous years.

I've started with .243 with a plan to get to .308 and .223 this winter. Also just booked into a 300 BLK setup, although I'm thinking it doesn't apply to this conversation.

In my forum and YouTube study there seems to be some argument about neck sizing vs full length resizing. Just wondering what INGO thinks about this?

TIA

 

[sugarcreekbrass]

I have never picked up range rifle brass. All of mine I bought new or collected from fired factory ammo. New brass gets full sizes before the first load. Anything else I have just neck sized. This ammo is just for my rifle. If you plan on using the ammo in different guns, you will want to full length size to make sure it chambers in the different rifles. From what I was taught, as long as you can chamber and cycle to round, just do a neck size. It will prolong the brass life.

 

[1911ly]

I neck size everything for bolt action. Can't do that for semi auto. I keep brass & ammo grouped per rifle ( A must ). I full length size about every 4th reload. I have 300wm brass that is 7 times fired and still going. My cousin never neck sized until he saw the life I get out of my brass. He usually got around 3x on 300wm before a split case. I am sold on it. He is now too. I got him dies for Xmas last year.

 

[natdscott]

Anything for an autoloader gets FL resized every firing, preferably with the shoulder pushed back 0.003-0.005". I have run my AR rifles at ~ -0.002", but they are VERY clean, fired single shot, the F/A is used,....and it is still probably not advisable.

Bolt gun rounds of mine are all FL sized in good dies, but the shoulder is only moved 0.001" or thereabouts EVER after it was fired the first time (which does almost all the damage right there).

But hey, most rifles do not shoot more accurately due to neck-only sizing. There...I just want to get that out there.

To attain the best chance at accuracy, bottleneck rifle cartridges in the chamber MUST be centered in the chamber at ignition. This is only done by two methods:

1) With Benchrest (the sport) rifles, chambers are typically tight enough that the casing BARELY has enough space to expand and release the bullet, much less rattle around appreciably. Sizing is almost always neck only because that's all that needs sized. They only fire 5's to 10's of rounds at a time, cleaning between each salvo. Too much fouling, or even a spare grain of powder allowed into the wrong place on one of these rifles can be the end of a day...or the end of a rifle. So practically speaking, this is a non-option.

2) For everybody else, the casing must be allowed to find it's own center when the pin falls. The properly sized casing is pushed forward until the shoulder of the casing contacts the internal shoulder of the chamber, and voila, it's centered up.

Where guys screw the pooch on this whole thing (as far as accuracy is concerned) is neck sizing, or only minimal "skimming" of the body of the casing. If the Web and body of the casing is allowed to grow unchecked, after only a couple firings, the BACK of the casing is now dictating where and how the round centers in the chamber...

...and given uneven expansion, unconcentric casings, spring loaded ejectors, etc... The rear end of the casing usually does a ****-poor job of axially aligning rounds.

Too, case LIFE is almost never cut short by body sizing. Casehead Separation is most often brought about by pushing the shoulder back too far. As the casing is fired-sized-refired-sized...the head of the casing is forced to continually REAAACH back'ards to the boltface the entire 0.010" you are mistakenly hotdog-in-hallway sizing the casing (because that's what RCBS said to do).

The brass at the web is 3/4 hard as it is from the box, and it only gets harder every time you fire it. No going back. So the harder it gets, the less it has ability to stretch, and the whole while it is STILL reaching, and STILL not getting that thinning material pushed back into place (you can't...once it's stretched in that spot, it's done fo'eva), and sooner or later... you fire it, the ring of thinned brass at the web/body junction is too thin, and too small, and the casing blows a hole in the side, or plasma cuts the entire casehead off.

The shooter also gets a face full of brass particles, burning powder, and gasses at 25,000 psi.

So anyway. That, and split necks are the most common case failures from reloading.

Split necks are prevented by not overly sizing the neck UP, and down, and UP, and down...and can also be helped by regular annealing. Here's an example of "too much working": Say your .243 casing has neck thickness of 0.0014". That means your loaded round neck diameter is about 0.271". This round is then fired in a chamber with 0.005" annular clearance (a lot, but not uncommon in factory rifles)...so it springs back just a touch from the chamber walls, and you end up with a fired OD of 0.280".

Well ****fire...that's aways from 0.271", in't it? Nothing to be done though. Not until you have to call Krieger for a tube.

So what do we do then? We cram that neck back into our little FL die from RCbLymLee, and hope everything is fine.

That die, being that it was made by lawyers as much as the rifle's chamber was...is awfully likely to size that neck down to 0.267" or even smaller. WAY too far.

All you NEED is to get the neck back down to about 0.002-3" tension on the bullet. In this example, that'd be about 0.269" OD.

So see what we did?! We forcibly flexed a 0.014" sheet of brass through a range of almost it's entire thickness.

THAT kind of working is what hardens brass in a hurry. Hard brass = no flex where it MUST flex...and cracks and split necks are what you get. Anything you can do to reduce that movement range (like getting better/custom/bushing dies) is a positive. Assuming you are not ready for custom chamber reamers and fitted brass, you have to control your tooling. That, and know what processes are moving what brass where. An FL die that is sizing the body of the casing down 0.002" can be a problem as much as the chamber that was too large in the first place...but the end result is a 7mm Rem Mag casing that is PO'd.

But FL sizing is not a problem for accuracy OR case life unless you MAKE it the problem, or you get a die from a die maker, and because you aren't paying attention and measuring, it is not really compatible with your chamber...so it is a de facto problem.

Redding S-Type FL dies are a decent option if you want to control neck OD/ID, but still need FL sizing, and a plain ol' FL sizer from a good brand is usually okay, honestly. But you need to MEASURE it and see what it is giving you WITHOUT the expander ball installed. If that neck figure is more than 0.004" UNDER loaded round diameter, you need to take action.

-Nate

 

[Broom_jm]

I neck-size for bottle-necked cases that are fired from bolt-action rifles.

I FL size for anything going through a semi-automatic rifle.

I partial FL size cases, setting the shoulder back just 2 or 3 thousandths, for everything else.

The first step is knowing your chamber and knowing your dies. The goal is to size your case ONLY enough for it to feed and chamber properly. Figuring out how much sizing that will take is the challenge. If you don't want to get that deep into it, meaning case life is not that big of a concern and you don't want to go through the process of determining what size your chamber is compared to your dies, then just FL size all of your cases. In many instances you will get lucky and the two dimensions will be close enough that it won't matter. If you decide you're willing to go down this particular rabbit hole, be advised that there is a fair amount to learn.

 

[Yeah]

For SAAMI versions of the cartridges listed I typically bump shoulders with an FL die nearly always, running the case further into the die only when the brass is calling for it during the process of setting up the die.

For steeper shoulders I neck size more than FL, though the difference between that and an FL bump is minimal. Were I to have only 1 sizing die per chambering it'd be FL, simply because properly setting up the sizer for the specific brass/chamber combination being processed is of far more importance.

 

[bigedp51]

Your cartridge case should fit the chamber like a rat turd in a violin case.

Below Kevin Thomas of "Team Lapua USA"

BelowErik Cortina of "Team Lapua USA"

[video=youtube;lLG2kSrD40g]https://www.youtube.com/watch?v=lLG2kSrD40g[/video]

 

[natdscott]

Yuppers. Kevin is a good guy, and highly competent.

I think (hope) we are getting something done in this thread!

"...sized just enough..." is indeed what we want, and the only way to get that is to PAY ATTENTION, think for YOURSELF, and invest in TOOLS that measure in real quantitative terms.

Bump gauges from Sinclair come to mind. Hornady LNL works too.

REAL numbers...not go/no-go chamber checkers.

 

[bwframe]

This is what we're talking about, right?

[video=youtube;c9_QMh72AmI]https://www.youtube.com/watch?v=c9_QMh72AmI[/video]

 

[Broom_jm]

So, we have a "Team Lapua" guy who needs ammo to "work in a variety of different guns" and a competition bench rest shooter with custom-reamed chambers and sizing dies
telling the average shooter not to neck-size.

One of our own forum members did an EXTENSIVE test of full-length versus neck-sizing brass, as well as annealing. ( https://www.indianagunowners.com/fo...ing/140337-new-brass-life-test-annealing.html ) Read this and then test for yourself. Don't be so quick to trust the word of "experts", especially those who are working with firearms and tooling the average reloader will never spend the money to buy and use.

It all boils down to this: Most of the time, when you "full-length size" a case, the die doesn't decrease the diameter of the case head and it doesn't move the shoulder back. As a result, most of the time, when you FL size, you really just neck-size. Why is that? It's because brass has elastic properties, such that when you fire a round in your chamber, the brass expands to complete fill the chamber (while under heat and pressure) but then retracts to a size that is already smaller than the internal dimensions of your FL sizing die. If you extract an empty case from your chamber, and you can load it right back into that chamber with no added resistance in closing the action, why in the world would you touch the body of that case with a die? The ONLY thing you need to do is resize the neck to allow sufficient tension to hold the next bullet.

The guy running semi-auto ammo in competitions where speed and reliable function matters...this doesn't apply to him. The guy going off on a rant about neck-sizing...has spent thousands of dollars on custom reamers to cut both his chamber AND his sizing dies. His GOAL is to size brass as little as possible. For most shooters who want to increase case life and improve accuracy, neck-sizing is still a perfectly viable way of doing so. It's not like metallurgy or dimensional tolerances have change since the time when Al Gore invented the Internet! Neck-sizing has worked VERY well for generations; test it out for yourself and you'll see it has definite advantages for most reloaders.

 

[bigedp51]

Chambers and dies vary in size, if you have a chamber at SAAMI maximum diameter and a die at minimum diameter you can shorten case life.
Example, I have a standard Lee full length .223 die that will reduce the case diameter more than my RCBS small base die will.

Below these .308 cases were fired in a brand new Savage rifle with the die making hard contact with the shell holder with press cam over. The case data below is ball park because the amount of shoulder bump was not given, nor was how much the case diameter was reduced.

Below German Salazar from his website "The Rifleman's Journal" is answering a question about partial full length resizing and why you are better off completely full length resizing.

Reloading: Partial Neck Sizing
by German A. SalazarReloading: Partial Neck Sizing
http://riflemansjournal.blogspot.com/2010/06/reloading-partial-neck-sizing.htmlReloading: Partial Neck Sizing

"Now the last scenario, a full-length sized case in which the neck is also fully sized. There is clearance at the neck and in the body of the case, the closest fit anywhere is the bullet in the throat. If the neck to bullet concentricity is good (although it needn't be perfect), then the bullet will find good alignment in the throat and the case body and neck will have minimal influence. Let's not forget that the base of the case is supported by the bolt face or the extractor to a certain degree as well; this is yet another influence on alignment. As you can see, there are several points from base to bullet that can have an effect. My procedure is to minimize the influence of those that I can control, namely the case body and neck, and let the alignment be dictated by the fit of the bullet in the throat and to som extent by the bolt's support of the base. Barring a seriously out of square case head, I don't think the bolt can have a negative effect on alignment, only a slightly positive effect from minimizing "case droop" in the chamber. Given that a resized case will usually have a maximum of 0.001" diametrical clearance at the web, this isn't much of a factor anyway."

NOTE,at the Whidden custom die website they tell you they get the most concentric cases from non-bushing full length dies.

 

[bwframe]

So, we have a "Team Lapua" guy who needs ammo to "work in a variety of different guns" and a competition bench rest shooter with custom-reamed chambers and sizing dies
telling the average shooter not to neck-size.

One of our own forum members did an EXTENSIVE test of full-length versus neck-sizing brass, as well as annealing. ( https://www.indianagunowners.com/fo...ing/140337-new-brass-life-test-annealing.html ) Read this and then test for yourself. Don't be so quick to trust the word of "experts", especially those who are working with firearms and tooling the average reloader will never spend the money to buy and use.

It all boils down to this: Most of the time, when you "full-length size" a case, the die doesn't decrease the diameter of the case head and it doesn't move the shoulder back. As a result, most of the time, when you FL size, you really just neck-size. Why is that? It's because brass has elastic properties, such that when you fire a round in your chamber, the brass expands to complete fill the chamber (while under heat and pressure) but then retracts to a size that is already smaller than the internal dimensions of your FL sizing die. If you extract an empty case from your chamber, and you can load it right back into that chamber with no added resistance in closing the action, why in the world would you touch the body of that case with a die? The ONLY thing you need to do is resize the neck to allow sufficient tension to hold the next bullet.

The guy running semi-auto ammo in competitions where speed and reliable function matters...this doesn't apply to him. The guy going off on a rant about neck-sizing...has spent thousands of dollars on custom reamers to cut both his chamber AND his sizing dies. His GOAL is to size brass as little as possible. For most shooters who want to increase case life and improve accuracy, neck-sizing is still a perfectly viable way of doing so. It's not like metallurgy or dimensional tolerances have change since the time when Al Gore invented the Internet! Neck-sizing has worked VERY well for generations; test it out for yourself and you'll see it has definite advantages for most reloaders.

Thanks for link to that other thread. I remember seeing that a few years back, when I had less understanding of the particulars. I'm going back to reread.

 

[bigedp51]

Thanks for link to that other thread. I remember seeing that a few years back, when I had less understanding of the particulars. I'm going back to reread.

When you get done reading that post about annealing ask yourself what does that post have to do with the benifits of neck vs full length resizing. (Nothing)

The main point of full length resizing is uniformity and not having the case body have a aligning effect with the bullet in the throat. If the case has unequal case wall thickness the thin side of the case will expand more and the case will warp and become banana shaped.

Neco case gauge

Concentricity, Wall Thickness and Runout Gauge
The NECO, patented, Case Gauge is the most versatile instrument available for measuring the various accuracy determining factors of cartridge cases, bullets and loaded ammunition. No other gauge can measure all of the following: 1.Banana curvature of case. 2.Wall and neck thickness variations. 3.Case head squareness. 4.Banana curvature and out-of-round shape of individual bullets. 5.Runout of seated bullet. 6.Total runout of loaded cartridge. The "Case Gauge" can be used to measure cartridges from .17 cal to .50BMG by purchasing the appropriate "chord anvil".

 

[bwframe]

It appears as this bumping the shoulder back .002 is less than the routine full length resizing? Similar to neck sizing in that it's moving/stressing less metal each time vs what we would normally call full length resizing?

 

[bigedp51]

Bumping the shoulder back .002 would be adjusting the die to push the case shoulder back .002 below the red dotted line in the illustration below. One method would be to use Redding competition shell holders that allow the die to make hard contact with the shell holder and the press cam over. Another method would be to use headspace control shims under the dies lock ring. Or by using feeler gauges between the shell holder and die for adjusting the amount of shoulder setback or shoulder bump. I have dies if not adjusted for minimum shoulder that will push the shoulder back .009 or more and cause case head separations.

I use a Hornady cartridge case headspace gauge to measure my fired cases and then use my Redding competition shell holders for the correct shoulder bump.

The Redding Competition Shellholder Kits consists of five shellholders in varying heights with increments of .002". This allows you to increase or decrease the case to chamber headspace without adjusting the dies. Meaning these five shell holders will push the case .002, .004, .006, .008 and .010 "less" than a standard shell holder and never touch the die.

 

[Broom_jm]

And now we're into the really expensive solutions to the problem(s) neck-sizing fixes without even thinking about it. The concentricity gauge is $170 and the custom shell holder set is $55 PER CASE HEAD SIZE that you reload. Even if all you shoot are .378's (223) and .473's (308), you're still looking at an additional $110 in shell holders, only ONE of which you will actually use, once you know which one you need...the rest just sit there, doing nothing!

All of that cost and complicated measuring to accomplish something very simple; sizing your case as little as need be for it to function and be accurate. Again, if your case comes out of the chamber with every dimension being small enough that it chambers freely immediately after firing, ALL you need to do is neck-size. When your empty cases won't chamber freely, all you have to do is turn your FL sizing die in 1/4 turn at a time until they do...then you're back to good. (You can also just use that method and forget about all this other nonsense.)

Competition shooting has introduced costs and complexities into the reloading process that are critical, if your goal is to go from the 5's to the 3's or even lower: Those processes can be pursued by your average Joe Shooter or Fred Hunter, but they aren't needed. A FL sizing die, set to partially size the case, or the combined use of a neck-sizing die (most of the time) and a FL sizing die (adjusted properly) is all ya need. You don't need a micrometer or a concentricity gauge to get there, either. In general, your case life will be much better and your accuracy will improve. In some situations, like those mentioned above (big chamber, tight dies) you could see dramatic improvements in both. If you've got a chamber that happens to match your dies very well, none of the above will make much difference, even the expensive stuff.

It's great to read about all of this stuff, but the bottom line is to test things out at your reloading bench and through your rifles. Don't take my word for it, anyway. I only know what works for me.

Other guys, competitive shooters mostly, learn the advanced stuff and want to demonstrate that knowledge, but fail to recognize that it really isn't applicable to most of the folks who load and shoot their own ammo. Beware their guidance, unless you are willing to spend the money on rifles and equipment to make good groups into groups that win competitions.

 

[shibumiseeker]

Burl,

The TL;DR version of all of this:

FL size for your semi-autos.
Neck size for your brass used in a specific bolt gun.

IF your brass is precious AND you need to squeeze every bit of life out of them AND every last tenth of MOA accuracy, then you already have learned way, way more than the usefulness of the above advice.

If you know to the ten thousandth of an inch your chamber spec and exactly how much runout or variance of shoulder angle or whatever else it has, THEN you don't need to ask the question because you will already have an opinion on what is best for YOU and YOUR GUN. Otherwise, don't overthink it.

 

[natdscott]

It appears as this bumping the shoulder back .002 is less than the routine full length resizing? Similar to neck sizing in that it's moving/stressing less metal each time vs what we would normally call full length resizing?

No, that is conventional FL sizing for a Bolt Action rifle. Depending on the FL die, you are sizing the ENTIRE casing by the time it bumps the shoulder at all. If you sit and think about the internal dimensions of the die, you'll find that the die must be completely filled before it starts to hit the shoulder...ergo, any body sizing that is going to size has already BEEN sized by that point.

0.001-0.002" bump for bolt guns.

0.003-0.005" bump for gas guns and other autoloaders.


You seem awfully interested in learning what there is to learn. I want you to please buy a copy of this book: Zediker Publishing

Despite a semblance of a bias from some here (I'm looking at you, broom!) against things stemming from competitive shooting, the information in this book is excellent knowledge to have, even if you don't use it all the time for every rifle.

I am a perfect example. I load 1,000 yard .223 ammo that is probably as precise as any made anywhere by anybody, whether I can hold it or not. Then I turn around and load .357 to just basic field standard, and maybe my .243 ammo is somewhere in the middle. I don't seat everything with a Jones mic die with charges weighed on a milligram balance with turned neck Lapua...

But you have to HAVE the knowledge to make intelligent and safe decisions to go against the grain.


-Nate

 

[bigedp51]

I use the +.004 Redding competition shell holder to average .003 shoulder bump for my AR15 rifles. If I used the standard RCBS shell holder it would bump the shoulder back .007 and cause the case to stretch in the base and cause case head separations. I also have a Savage bolt action .223 and use the +.002 shell holder for .001 shoulder bump.

The advantage to these shell holders is it allows the die to make hard contact with the shell holder with press cam over. This eliminates any flex in the press and more uniform shoulder location after sizing. You will use several of the Redding competition shell holders depending on the brand case, annealing and the amount of brass spring back.

Another advantage to the competition shell holders is once the die is adjusted you never touch the die again and use the shell holders to adjust the amount of shoulder bump.

There is nothing wrong with having gauges, I have Remington .223 cases with over .009 neck thickness variations. And my Redding neck thickness gauge is used to sort cases and check the quality of the brass.

I also have the two runout gauges below.

And these gauges measure runout two different ways.

I also worked part time in a chain sporting goods store and got a very good discount on reloading equipment and dies. I have seven different type and make .223 dies and tested them for neck and bullet runout. And my Forster full length .223 die produced the least neck runout and the neck sizing dies produced the most neck runout.

Bottom line, at the Whidden custom die website they tell you they get the most concentric cases using non-bushing full length dies. And this is because neck sizing dies do not fully support the case body. Meaning the neck sizing dies do not hold the case body and neck in perfect alignment.

If you remove the expander from a full length die and size a case it will be as straight and concentric as it ever will be. And as long as your expander is centered and the inside of the case neck is lubed you will make straight concentric cases.

I'm 67, retired and have been reloading for over 47 years and have bought most of my gauges since retiring. And you will never know if you are making reloading mistakes if you can't check your results. And your biggest problem today is the quality of Remchester brass and the fact that the stock holders have their grip on quality control.

 

[Broom_jm]

Burl,

The TL;DR version of all of this:

FL size for your semi-autos.
Neck size for your brass used in a specific bolt gun.

IF your brass is precious AND you need to squeeze every bit of life out of them AND every last tenth of MOA accuracy, then you already have learned way, way more than the usefulness of the above advice.

If you know to the ten thousandth of an inch your chamber spec and exactly how much runout or variance of shoulder angle or whatever else it has, THEN you don't need to ask the question because you will already have an opinion on what is best for YOU and YOUR GUN. Otherwise, don't overthink it.

Best post of this thread: I am humbled.