Neck sizing only


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falldowngoboom
July 14, 2009, 06:35 AM
Hi all,

I'm new to reloading and planning to get started with the lee loader. I plan on using the same brass (30-06) in the same bolt action. As long as I stick to this, is there any reason I will need to FL resize at all? I do plan on trimming the necks.

Also, is it safe to take measurements of the cases I've fired in my rifle and assume they are appropriate case dimension for my specific rifle (except for C.O.A.L since the neck will stretch forward)?

I'm aware that in my situation, I would have to sort through once-fired brass that I BUY to find ones useable for my chamber.

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Grumulkin
July 14, 2009, 07:07 AM
The Lee Loader? That's what I started with many years ago.

Trimming cases is important. You should get by with only neck sizing.

You could take measurements of cases fired in your rifle and those dimensions would be appropriate. If you're merely trying to decide if the brass will fit in your rifle, it would probably be a lot faster to just attempt chambering it in your rifle.

Bart B.
July 14, 2009, 07:10 AM
This might be a reason.

When it was "the" round used in high power rifle competition, folks winning the big matches and setting the records with bolt action rifles full length sized their cases. Just be sure you don't set the fired case shoulder back only 1 to 2 thousandths of an inch nor reduce fired case body diameters by more than 3 thousandths.

Rimless bottle neck cases get shorter when fired. Measure a new case length, fire it, then measure it's length again to see how much it shortens. The case expands to fill the chamber then shrinks back a tiny bit; it's body diameter is larger than when new and unfired. That draws brass back from the neck. Neck sizing will lengthen a fired case neck a little bit, but full length sizing a fired case will lengthen the whole case somewhat more. You'll need to trim the case back a few thousandths after several reloads.

falldowngoboom
July 14, 2009, 07:47 AM
You could take measurements of cases fired in your rifle and those dimensions would be appropriate. If you're merely trying to decide if the brass will fit in your rifle, it would probably be a lot faster to just attempt chambering it in your rifle.
Grumulkin, I thought about this, but is there danger of getting the case stuck in the chamber? Also, will the neck edge potentially scratch the chamber, particularly if the case is too large?

When it was "the" round used in high power rifle competition, folks winning the big matches and setting the records with bolt action rifles full length sized their cases. Just be sure you don't set the fired case shoulder back only 1 to 2 thousandths of an inch nor reduce fired case body diameters by more than 3 thousandths.

Thanks for the pointers. Something to think about if I decide to get more serious, but for now I'm reloading for hunting and plinking. Are there two schools of thoughts here though? Because I've also read that competition benchrest shooters like to fireform their cases then only neck-size them for subsequent reloads to achieve better accuracy.

Rimless bottle neck cases get shorter when fired. Measure a new case length, fire it, then measure it's length again to see how much it shortens. The case expands to fill the chamber then shrinks back a tiny bit; it's body diameter is larger than when new and unfired. That draws brass back from the neck. Neck sizing will lengthen a fired case neck a little bit, but full length sizing a fired case will lengthen the whole case somewhat more. You'll need to trim the case back a few thousandths after several reloads.

Pardon my potential ignorance here, but I thought the entire case expands to fill the chamber. This would include the shoulder of the casing expanding to the end of the chamber, right? Also, from what I've read, I thought a fired case neck actually accumulates brass instead of losing it?

(From the Lyman Handbook)... "The walls of a case become thinner as it stretches from repeated firings and resizings. As a result, the neck section will thicken because of the forward brass flow."

Am I somehow misinterpreting this?

lordgroom
July 14, 2009, 08:50 AM
After firing the case swells to chamber dimensions and then contracts, which allows the case to be ejected from the chamber. Therefore it is should be small enough to chamber in your rifle without problems. When chambering a fired casing don't foprce it if it will not go.

There is little risk of scratching the chamber.

Bart B.
July 14, 2009, 09:15 AM
falldowngoboom, there's a lot of misinformation in print (in books, magazines and on line forums) regarding what happens when a rimless bottle neck case is fired. Most of it's based on improper or incorrect case measuring for each phase a new case goes through from first firing through reloading then firing again. Here's what happens with a new .30-06 round of ammo.

When loaded, it rests in the chamber until the firing pin strikes it. When the primer's struck with some 25 to 30 pounds of force, that energy drives the case forward against the chamber shoulder. The force is enough to set the shoulder back shortening the head-to-shoulder length a few thousandths. This also pushes case brass into the chamber neck making the neck a bit longer. As the powder burns increasing pressure and expanding the case body against the chamber wall, that stretches the brass pulling the case neck back a bit in the chamber's neck. At the same time, the case body stretches back until the case head's stopped against the bolt face. The resultant case dimensional change is its body is now greater in diameter at the shoulder-body junction as well as the pressure ring which is about 2/10ths inch in front of the case head. More brass moved expanding the case body diameter than changing the neck dimensions so the fired case is now shorter.

When this fired case is full length sized, its body and neck diameters get reduced and the brass has to move someplace, so the case gets longer. The dimensional changes are such that after a new case is fired it gets a few thousandths of an inch shorter, but resizing it makes it a couple thousandths inch longer than when it was new. With minimum full length sizing, the case will be almost 1/1000ths longer after each cycle. The more a fired rimless bottle neck case has its diameters reduced when sized, the more growth in length it has from each fire and resize cycle it goes through. This is what the quote means you mentioned:

"The walls of a case become thinner as it stretches from repeated firings and resizings. As a result, the neck section will thicken because of the forward brass flow."

It mentions "firings and resizings" which is the key phrase.

As most folks using full length sizing dies on such cases work the brass too much by setting the shoulder back too far (more than 2/1000ths) and reducing fired case diameters too much (more than 3/1000ths). And they may well get better accuracy and longer case life with neck only sizing their fired cases. This will cause a lot more brass to flow forward thinning the case at its weakest point; the pressure ring about 2/10ths inch in front of the case head. Folks who full length size .30-06 cases the best way usually get a few dozen reloads per case; sometimes more. Neck thickness doesn't increase any significant amount but case length will grow about 10/thousandths after 10 fire & resize cycles and need to be trimmed back. I've shot and fired a .308 Win. case almost 50 times full length sizing this way with excellent accuracy, low muzzle velocity spread and didn't anneal the neck at all. Others have done the same thing.

Benchresters have used neck sized cases for years but there's more of them full length sizing nowadays. They don't reduce fired case diameters nor set shoulders back more than 1 or 2 thousandths and get exceptional case life. The claim made by neck only afficianados is it centers the bullet better in the barrel. Both neck only and full length sized cases center the neck and bullet perfectly when fired as their shoulder's forced to center in the chamber shoulder when the firing pin drives the case forward. It doesn't matter how much clearance there is between case neck and chamber neck. And both types have the case back end pressed against the chamber by the extractor, so the back of the case isn't ever perfectly centered in the chamber. Every round fired has its long axis a tiny bit misaligned with the chamber axis. Not many folks realize this is what happens.

loadedround
July 14, 2009, 09:28 AM
FWIW: I am very fond of and collect and shoot Ruger #1 Rifles. Three of my favorite rifles have tuned Moyer triggers, and have had extensive bedding and metal work done on them and all three are consistent less than MOA shooters. I have found that if I fire new cases or full length sized cases, my groups have a tendency to open up almost 1/4 to 1/2". Therefore I segregate and only neck size these cases. FYI, these calibers are 22K-Hornet(was a 22 Hornet, 223 Rem, snd 22-250 Rem in 1B models. :)

Smokey Joe
July 14, 2009, 01:58 PM
Falldowngoboom--you said:I thought about this, but is there danger of getting the case stuck in the chamber? Also, will the neck edge potentially scratch the chamber, particularly if the case is too large?IF the case gets stuck in the chamber, you can run a cleaning rod down the bbl from the muzzle end until the rod contacts the base of the case, tap on the handle end of the rod, and your case will pop out of the chamber. Of course, this won't work if the case is really, really stuck, but you should never have closed the bolt that hard in the first place. When the bolt stops on the case, stop pushing on the bolt.

Brass is a lot softer than steel, especially heat-treated steel like a firearm receiver, so there is no worry abt scratching yr steel chamber with a brass case.

As to eventually needing to FL resize, the best answer is, "it depends." If you've trimmed the cases to length and neck-sized them, and they still won't chamber in your rifle--or chamber only with great difficulty--then it's time to FL resize. I've had that happen with my .300 WSM, after 5 reloadings. It usually doesn't happen with my '06's until the necks start splitting anyhow, and then I scrap that whole lot of brass. As always, YMMV.

243winxb
July 14, 2009, 02:26 PM
As long as I stick to this, is there any reason I will need to FL resize at all? Full Length Resizing will be needed soon or later. How soon depends on the powder charge.Also, is it safe to take measurements of the cases I've fired in my rifle and assume they are appropriate case dimension for my specific rifle (except for C.O.A.L since the neck will stretch forward)? If firing factory ammo that is loaded to high pressures you can get an idea of chamber size. Don't forget brass will spring back after firing and be .001" or maybe .002" smaller than the chamber. The web area near the head should not expand.I'm aware that in my situation, I would have to sort through once-fired brass that I BUY to find ones useable for my chamber. This will not work, unless your rife has a very large chamber. is there danger of getting the case stuck in the chamber Yes, before firing, after firing it can be removed.Pardon my potential ignorance here, but I thought the entire case expands to fill the chamber. This would include the shoulder of the casing expanding to the end of the chamber, right? Yes for the most part, the web area does not expand. In a large chamer the shoulder can move back on firing. This is because the body expands outward.Also, from what I've read, I thought a fired case neck actually accumulates brass instead of losing it?

(From the Lyman Handbook)... "The walls of a case become thinner as it stretches from repeated firings and resizings. As a result, the neck section will thicken because of the forward brass flo Some areas of the body will thin and come apart over time and pressure. The area right at the neck shoulder junction can get thicker, but the neck overall can thin from being worked in some dies with an expander button. Having started loading using a Lee Hammer loader, i would tell you to save your money for a press and dies. A scale is needed for both, plus a case trimmer. And a few other item that i am sure i forgot. Photos here http://www.photobucket.com/joe1944usa

falldowngoboom
July 14, 2009, 05:00 PM
Thanks for all the answers and especially to Bart B for that detailed explanation. I really appreciate it. :D

Am I right to conclude the main function of full-length resizing (for cases previously fired in the same bolt action) is to prolong case life by pushing the shoulder back ever so slightly, thereby thickening up the case wall and keeping wall thinning at bay?

When the primer's struck with some 25 to 30 pounds of force, that energy drives the case forward against the chamber shoulder.

Is this true even of bolt actions? I thought the bolt was supposed to hold the case in place during firing?

Will you all indulge a few follow up questions? I had no idea reloading was so complicated... :confused:

If I can chamber and extract an already fired casing, but it is very tight, is that still okay to use for reloading? Is being able to chamber and extract it the only thing that matters in a bolt action? (Other than the neck being too long and the case being in good condition, of course.)

Also, is there a standard for how much headspace is allowable for a 30-06? Would it be the 2/1000ths of an inch you mentioned, Bart B? I can't seem to find anything about headspace tolerances in my reloading book.

243winxb
July 14, 2009, 05:20 PM
Am I right to conclude the main function of full-length resizing (for cases previously fired in the same bolt action) is to prolong case life by pushing the shoulder back ever so slightly, thereby thickening up the case wall and keeping wall thinning at bay?
FLRS is done so the loaded ammo will chamber 100% of the time.If I can chamber and extract an already fired casing, but it is very tight, is that still okay to use for reloading? Yes, if you want to use your bolt to size the brass.I have seen people beat the bolt handle closed with a block of wood. They got the loaded round starting into the chamber and could not get it out.Is being able to chamber and extract it the only thing that matters in a bolt action? Yes, plus it does have to feed from the magazine.

rcmodel
July 14, 2009, 05:36 PM
is to prolong case life by pushing the shoulder back ever so slightly, thereby thickening up the case wall and keeping wall thinning at bay?Nothing could be more wrong.

All fired cases have to be re-sized before you can reload them.
This can be Neck-Sizing, which only reduces the diameter of the neck so it can grip a bullet again.
It does not move the shoulder back, and does prolong the life of the brass.

Full-Length sizing returns the whole fired case back to new factory dimensions.
It does push the shoulder back slightly, but only to where it was to begin with.

IMO: All new reloaders should use full-length sizing to begin with.
You have enough variables to play with without dealing with hard bolt closing, etc from neck sizing only.

Once you master reloading and making perfect factory spec ammo, then you will have learned enough to start playing with neck sizing if you feel the need.

Most people would be perfectly fine if FL sizing was all there was.

rc

falldowngoboom
July 14, 2009, 06:12 PM
RC, I was asking in the context of my OP, not in general. I will be neck-sizing only because I don't have the option to FL resize since I'm using the Lee Loader. I do, however, plan on matching brass to my bolt action and not firing the cartridges in any other gun, so I was asking what the point of FL resizing would be in the specific context of doing so with once-fired brass from a given bolt action (as opposed to neck-sizing only).

I'm kinda getting confused here, because Bart B said,

"The dimensional changes are such that after a new case is fired it gets a few thousandths of an inch shorter, but resizing it makes it a couple thousandths inch longer than when it was new."

Does FL resizing shrink the case or lengthen it?

IMO: All new reloaders should use full-length sizing to begin with.
You have enough variables to play with without dealing with hard bolt closing, etc from neck sizing only.

Are there inherent dangers here that I'm not aware of? What other issues are there other than the bolt being a bit more snug than factory spec ammo? I'm okay with dealing with things that are just inconvenient especially since, as I understand it, chambering shouldn't be a problem once the brass has been fired in my particular bolt-action.

Walkalong
July 14, 2009, 06:21 PM
Are there inherent dangers here that I'm not aware of? What other issues are there other than the bolt being a bit more snug than factory spec ammo? I'm okay with dealing with things that are just inconvenient especially since, as I understand it, chambering shouldn't be a problem once the brass has been fired in my particular bolt-action.
It just adds more things to the equation. I agree with rcmodel 100% that for folks just starting in reloading, full length resizing for rifle calibers is best. Then go from there.

rcmodel
July 14, 2009, 06:35 PM
Does FL resizing shrink the case or lengthen it? When the round is fired, the case expands to fill the chamber tightly and may also stretch to fit the available headspace in the rifle. After the pressure drops, it contracts in the chamber, but remains larger then it was before firing.

When it is FL sized, it is squeezed back down and the excess brass makes the neck longer because that is the only place in the die it can go.
Then we trim if necessary and the case is back to factory specs again.

So yes, firing makes it bigger around, and may make it shorter.
Sizing makes it longer and smaller around.

rc

243winxb
July 14, 2009, 06:43 PM
Lee Loader, Bottom Line. Soon or later you MUST Full Length Resize.

falldowngoboom
July 14, 2009, 07:14 PM
Thanks for clarifying RC. :)

Bart B.
July 14, 2009, 11:00 PM
fallingdowngoboom's comment:I'm kinda getting confused here, because Bart B said,

"The dimensional changes are such that after a new case is fired it gets a few thousandths of an inch shorter, but resizing it makes it a couple thousandths inch longer than when it was new."

Does FL resizing shrink the case or lengthen it?


Full length sizing a fired case lengthens it. Firing that full length sized case makes it shorter. rcmodel says good stuff about these events. But you're doing pretty good learning all this mechanical stuff about reloading.

The way my full length sizing die's are set up, a .308 Win sized case gets a couple thousandths shorter when fired, then lengthens that much plus almost another thousandth. After 10 shoot and resize cycles, the case has grown in length almost 7 to 8 thousandths; it gets trimmed back to an even 2.000 inches. Others may well get different numbers depending on the specific cartridge, die dimentions and how the die's set in the press. Even the amount of case lube can effect shoulder set back by a few thousandths; more with lots of lube, less with just a tiny amount.

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