I have a 300 mag custo
m based on the 300 h&h. I do not have the dies so may I reload using a 30 cal neck sizing die after fire forming some cases? Optik1

yeah.
till you need to full length resize, then your gonna have to figure something out.

Co9l thanks, I agree.

quote:

Originally posted by optik1:
I have a 300 mag custo
m based on the 300 h&h. I do not have the dies so may I reload using a 30 cal neck sizing die after fire forming some cases? Optik1

As state by Lamar, yes you can reload just by neck sizing provided your fired cases fit back in the chamber okay. Eventually you will need to FL resize.

Also will depend on the 30cal neck size die you have as to whether the body of your 300 mag custom cases fit up into the die to allow the neck to be sized. I have a 7mm neck size die that will do the 7mm Rem Mag and smaller 7mm cases but 7mm WSM cases (based on the 404 Jeffery case) will not fit up into this neck sizing die.

quote:

I have a 300 mag custo
m based on the 300 h&h. I do not have the dies so may I reload using a 30 cal neck sizing die after fire forming some cases?

No idea what why reloaders are invacuated with full-length sizing. If I fire a case in a chamber, I should know the length of the case from the shoulder to the head of the case before firing, I should know the length of the chamber from the shoulder to the bolt face, knowing both measurements should give me the opportunity to form first and then fire to cut down om all that case travel.

Reloaders insist on full-length sizing; I choose to adjust the die for minimum full-length sizing to cut down on all of that case travel. I adjust the die off of the shell holder, I can do that with a feeler-gage, or I could spend a lot of money on Redding competition shell holders.

F. Guffey

quote:

Originally posted by F. Guffey:

quote:

I have a 300 mag custo
m based on the 300 h&h. I do not have the dies so may I reload using a 30 cal neck sizing die after fire forming some cases?

No idea what why reloaders are invacuated with full-length sizing. If I fire a case in a chamber, I should know the length of the case from the shoulder to the head of the case before firing, I should know the length of the chamber from the shoulder to the bolt face, knowing both measurements should give me the opportunity to form first and then fire to cut down om all that case travel.

Reloaders insist on full-length sizing; I choose to adjust the die for minimum full-length sizing to cut down on all of that case travel. I adjust the die off of the shell holder, I can do that with a feeler-gage, or I could spend a lot of money on Redding competition shell holders.

F. Guffey

Not all cases can be partially resized in FL dies, WSM cases for instance will rechamber nicely into the chamber after firing but will not rechamber after only partially resizing in the FL die, they need to be FL resized with a good bump from the shell holder to the die mouth.

Aside from this, provided case shoulders are not pushed back each time to give excessive headspace leading to incipient case head separation, most cases ended up being retired from use due to case mouth splitting or enlarged primer pockets. FL sizing does not cause these issues bringing about early retirement of cases and the other advantage of FL sizing is that the reloaded ammo will fit other rifles.

I reload 7mm-08 ammo for three different rifles so always FL resize, never losing cases due to any defects arising from FL resizing.

The reason partial sizing in a FL die does not and cannot work, is that if you reduce the case body diameter any at all, it pushes the shoulder forward, thereby making it impossible for the case to fit back into the chamber.
OP is taling about neck sizing only; I hope.
I make the case fit back into the chamber, with a slight feel when closing the bolt, or just shy of that. Especially belted mag dies, sometimes size too much at the shoulder. FL sizing all the time will result in short case life if you are stretching your case each time and thinning it. Most do not realize the relatively huge tolerances allowed in cases, dies, and chambers.
Anyway, everyone must be specific when they use certain terminology.

quote:

The reason partial sizing in a FL die does not and cannot work, is that if you reduce the case body diameter any at all, it pushes the shoulder forward, thereby making it impossible for the case to fit back into the chamber.

Lyman, the sight company covered that many years ago, they covered the part about the case body forcing the shoulder forward, but they claimed the shoulder would take on the appearance of a radius if the case die does not contact the shoulder. That was a time before reloaders could move the shoulder back, I have always said it is impossible to move a shoulder back. That was a time when 'bump' was a function of the press.

F. Guffey

Why do you say you can't move a shoulder back? That is literally the function of a full length sizing die. We move shoulders forward and back all the time when making wildcat cartridges.
Partial sizing in a FL die usually does not work for the reason I stated, regardless of the resulting shoulder shape. It moves forward.

I am trying to understand this! If you partial size a case which I do often, how can the shoulder move forward if the sizing die still has the case in it. I partial size by putting a home made plastic washer(thin) betwix the die and the press just so I don't push the shoulder BACK. This has worked out for me many times as I have reloaded many cartridges 30 plus times and many are belted magnum cartridges. If a sizing die can push back a shoulder, how can it also allow one to move forward----I don't understand.

Inquiring minds want to know.



Hip

quote:

posted 21 August 2022 19:59 Hide Post
Why do you say you can't move a shoulder back? That is literally the function of a full length sizing die. We move shoulders forward and back all the time when making wildcat cartridges.

It is not that complicated, the shoulder I start with is not the same shoulder I finish with. The shoulder I start with becomes part of the neck and part of the case body becomes part of the shoulder. I do not know how you do it, you believe you tell the case what to do, it is impossible to move the shoulder back, again, the shoulder I start with is not the same shoulder I finish with. I can size a 30/06 case to 8mm57, it is easier to form the case, but I do believe I will lose you if I say form instead of size. Anyhow, the shoulder on the 8mm57 is .127" closer to the head case than the shoulder on the 30/06 case. I know you believe I moved the shoulder back .127", again the shoulder I started with became part of the neck and part of the case body became part of the shoulder; and then there is bumping like "I bump...'

F. Guffey

Okay, after thinking about it I now understand----DUH! But I have yet run into problems partial sizing where the shoulder moved forward and I was unable to seat the round in the chamber. My sole reason for partial sizing is to NOT move the shoulder BACK and to help prevent case stretching.

Hip

I assure you that I understand; I have been reloading and forming cases since 1966. And cutting chambers. I know full well what takes place in dies. You are just calling moving a shoulder back, something else.
This is also why we don't want to FL size belted cases, usually/often. Tolerances are huge on them and shoulders need to be left as fire formed, and NOT MOVED BACK with the die. Yes, it's very easy to comprehend.
Hip; you are lucky; you can't always partially size a case and still have it fit a chamber. All depends on tolerances in the system. Of course you are maximizing brass life by having it fit well.

Listen to dpcd.

Experience always beats armchair writers.

I used to read every hunting and shooting magazine found.

Learned a lot from them.

But, also found there was so much rubbish written as fact.

I reload for several hundred cartridges.

Some are one off wildcats I made myself.

I make my own dies.

have tried everything new sold.

And ended up using just standard FL length dies.

Except for some wildcats where I use sizing buttons.

If you think about it, if you have a case with any taper, the only contact a FL die backed off will have with the case is at the neck.

"Partial FL sizing" is essentially setting the die up so it does not contact the case fully.

If you have no die support at the shoulder, and you move brass at the body, it flows away from the contact and the shoulder will expand to where the the die support is- ie bigger than the chamber it was fired in. This is why you have to trim cases... the flow goes out to longer than it was before because the brass is flowing every direction from the die support.

If you are FL sizing only to the point of moving the case shoulder back 1-2 thousandths from where it was after firing, you are just not resizing the case all the way to die spec... just far enough that it is smaller than the chamber. It is larger than a minimum spec case, but still smaller than your chamber. Its also why if you reload for multiple rifles, that by just setting your case to barely move the shoulder that it may well not chamber in some of the rifles and will in others just fine.

Depending on the tolerances involved, I have seen FL dies that have had a very snug fit in some chambers.

It's all a matter of understanding what tolerances are. Your chamber the same each time, your die is different each time depending on how you set it up, but it is supposed to be at its minimum setting smaller than the smallest chamber- may not always work out that way, but that is what the design is supposed to imply.

quote:

Originally posted by Hipshoot:
Okay, after thinking about it I now understand----DUH! But I have yet run into problems partial sizing where the shoulder moved forward and I was unable to seat the round in the chamber. My sole reason for partial sizing is to NOT move the shoulder BACK and to help prevent case stretching.

Hip

quote:

If you think about it, if you have a case with any taper, the only contact a FL die backed off will have with the case is at the neck.

Please provide me with the opportunity to disagree, the first contact the die makes with the case is at the neck and then comes the part where the die contacts the case body.

I can shorten the distance from the shoulder to the case head when sizing, I cannot accomplish that task by moving the shoulder back. The shoulder I finish with is not the same shoulder I started with. There is absolutely nothing I can do about changing, I am convinced the shoulder moves forward when sizing/forming a case. I have trimmed .200" from the neck of a case after forming, by the time I start trimming I am trimming part of the first shoulder I started with, when finished I could finish with a new shoulder and the beginning of a new neck.

F. Guffey

I don't know but, I load thousands of rounds a year and have never encountered the problem(s) mentioned.
I am going by my experiences over many years and NOT encountered these problems and in many instances obtained extremely long case life.

Some examples
.256WM 3-4---my method 8-10 loadings formed from .357 brass
.30-06 now at 23
7mmRM now at 14
.375 H&H AI now at 20 formed from .340 WBY brass.

Hip

The case body in all (or almost all) cases are tapered.

Depending on the amount of taper and how far your tolerances are (and how much sizing you are doing- remember the chamber is tapered as well) for the diameter, for most rounds the body will not touch, assuming a minimal sized chamber, just like neck sizing. Belted cases likely will, as they tend to be oversized chambers by the tolerances involved.

If you are forming a new case, true, you can’t move a shoulder forward with a die, you need to blow it out by fire forming (or else start with a case without a shoulder…) but in effect every firing is fireforming that case to a larger than loaded ammo size - or else you cannot easily chamber it. Metal has some liquid type properties. It flows. “Pushing the shoulder back” has no relation to individual molecules, but rather the case is alternately being molded into a larger and smaller shape. This gives the lengthening (while thinning) the case and also the work hardening and metal fatigue. The term pushing back refers to the measured dimensions from the case mouth, not that you are cutting the shoulder out and setting it in a different spot. If the metal was not ductile, it wouldn’t work for cartridge cases.

The case metal will flow in all directions. When you resize, the only really free place to go is the unconfined dimension of overall length, the shoulder is not moving forward when you resize- you are squeezing it back, and the metal is now flowing to the case mouth under pressure.

In any case, partial full length sizing is a misnomer, as all you are really doing is full length resizing to a longer length and individualizing the loaded case to that rifle.

quote:

Originally posted by F. Guffey:

quote:

If you think about it, if you have a case with any taper, the only contact a FL die backed off will have with the case is at the neck.

Please provide me with the opportunity to disagree, the first contact the die makes with the case is at the neck and then comes the part where the die contacts the case body.

I can shorten the distance from the shoulder to the case head when sizing, I cannot accomplish that task by moving the shoulder back. The shoulder I finish with is not the same shoulder I started with. There is absolutely nothing I can do about changing, I am convinced the shoulder moves forward when sizing/forming a case. I have trimmed .200" from the neck of a case after forming, by the time I start trimming I am trimming part of the first shoulder I started with, when finished I could finish with a new shoulder and the beginning of a new neck.

F. Guffey

quote:

Originally posted by dpcd:
... You are just calling moving a shoulder back, something else.....

I agree.

I think Mr. Guffey may be focussing on a nit that's technically true, but is totally irrelevant to the point of the distance between the case head and the datum.

If I understand this correctly ...

When you FL size, you're shortening the distance between the datum and the case head.

Necessarily, brass flows away from the case head, through the shoulder and into the neck, often lengthening the case enough that it needs to be trimmed.

Necessarily, the entire shoulder (or most of it) will be moved towards the case head, even if the brass forming the shoulder is not entirely the same brass that it was before resizing (some of it will become neck brass).

And yeah, technially, the new datum would be relocated to a section of the brass that it hadn't been on before.

But "not the same brass" seems fairy obscure to me: The shoulder is defined by the shape and measurements of the case, not some piece of brass, which may wander to its heart's content as the brass is worked.

Ultimately the shoulder is the home of the datum, and where the datum is, the shouder is.

Wow, talk about gobble goop, size the neck not the shoulder, until firing gets a too tight case, then full length resize, and start all over neck sizing that case.

A possible exception might be to full length resize all "hunting loads" and be satisfied with about 3 or 4 max loaded firings..

On a 300 H&H or 375 H&H I blacken the neck with a match and run a case in the full length die to the base of the shoulder a bit at a time or until just barely snug, but not into the shoulder, cases seem to last a long time with that tapered case contrary to much BS by the full length crowd on those two calibers streatching cases...Its a good practive IMO..

quote:

Originally posted by dpcd:
... You are just calling moving a shoulder back, something else.....

I am saying the shoulder I start with is impossible to move back. I am sure in your 65 years of reloading you have had cases with artifacts on the case, I have scribed artifacts at the case body/shoulder juncture, and I have scribed a .375" datum on the shoulder. never have I ever had a scribed line, on the shoulder or case body juncture move back when sizing and or forming.

Calling it something else, I form at least 4 short cases from 30/06 cases, I knew from the beginning because of artifacts the 30/06 shoulder was not moving back. I knew when I used a hack saw to trim the case above the die all of that brass did not magically appear, it had to come from somewhere. I Knew the new shoulder was not the same shoulder I started with, and then for years reloaders were complaining about the dreaded donut.

F. Guffey

Partial full length sizing is the way to go for accuracy.

And yes, right before you got shoulder contact in the die the shoulder does move forward......right before you get contact....the brass has to go somewhere as you are now sizing down the base of the cartridge.

That's when you start very carefully adjusting the die down until you het two or three ten thousandths of shoulder bump....that's what one wants to gain the optimum chamber fit on fire formed brass.

The choice one makes,is whether one is hand loading for ultimate accuracy or reloading.....

.

quote:

Originally posted by F. Guffey:

quote:

Originally posted by dpcd:
... You are just calling moving a shoulder back, something else.....

. . . I am saying the shoulder I start with is impossible to move back.
F. Guffey

I guess I don't know where the datum is located. I'd always thought it was on the shoulder, and that the datum moved closer to the case base when a case is FL sized.

Where did I go wrong?

quote:

Originally posted by B L O'Connor:

quote:

Originally posted by F. Guffey:

quote:

Originally posted by dpcd:
... You are just calling moving a shoulder back, something else.....

. . . I am saying the shoulder I start with is impossible to move back.
F. Guffey

I guess I don't know where the datum is located. I'd always thought it was on the shoulder, and that the datum moved closer to the case base when a case is FL sized.

Where did I go wrong?

On a belted magnum, the datum is actually on the belt. The headspace gauges I have are basically 1.25" long and just "measure" the belt.

However, the argument here is this:
As a case is worked in a sizing die, the material in the body area may be pushed inwards by the die. This material "flows" slightly forward, moving the shoulder forward and making the case slightly longer. If the shoulder is contacted by the die, the material is not pushed back but is pushed inwards and thus continues to "flow" forward.

Thus, some of the material that was originally in the shoulder now ends up on the neck. This happens every time the case is worked, and is the reason why cases have to be trimmed and also why "donuts" are a problem in certain calibers.

But, it's not the whole shoulder, it only moves a few fractions of an inch per working. Else we'd all have head separations after the second firing. However, the more you move the shoulder around (by over-sizing) the more material flows.

Basically, everybody here is saying pretty much the same thing but using different words to do it.

quote:

I guess I don't know where the datum is located. I'd always thought it was on the shoulder, and that the datum moved closer to the case base when a case is FL sized.

Where did I go wrong?

The case does not have head space. a datum can be used to determine the length of the case from the datum to the case head. Why use a datum? The shoulder has a tapper, the only way to determine the location on a shoulder is with a datum; the most common datum is .375", and then there is the .400" datum, after that is the .420" datum. all of my datums are round holes. I make datums, all I do when making a datum is drill a hole, if I am working with the 30/06 family of cases I drill a hole that is 3/8" in diameter or .375". When measuring the distance from the datum to the case head most reloaders give up because they cannot get the case to stand up straight, I suggest they drill a hole that is the same outside diameter as the neck first and then drill the .375" datum diameter (datum) hole.

Where is the datum? I use blocks that are thick enough to prevent the case from protruding through the block, the surface on the bottom of the block is the bottom of the block and the top of the block is the datum as in 'measure from'.

Sinclair/Dillon tried to make a tool that never passe3d as a head space tool because the hole they drilled had a radius on what they called a datum, the radius lowered the datum, no matter how hard they tried the best they could do was make a comparator as in measure before and again after.

I make datums that are not case friendly, my datums have sharp shoulders, I scribe the datum on the case by twisting/turning the case, it is a good way to keep up with the direction the brass is flowing when sizing.

I formed 480 cases for a builder of wildcats that needed magnum cases formed from long belted magnum cases. 40 of the cases were bulged ahead of the belt meaning that part of the case was not supported at the belt/case body and none of the cases would fit a #4 RCBS shell holder.

He wanted me to bring 'the other #4 shell ho0lder' I brought a gasket cutting hammer to drive the cases onto the shell holder.

I would have reduced the diameter of the case ahead of the belt, but he did not have a collet that would fit.

F. Guffey

or drill through the block and then make bushings with an outside diameter of .374 +-- to use for centering/supporting the neck.

F. Guffey

quote:

Basically, everybody here is saying pretty much the same thing but using different words to do it.

Everybody? Thank you.

quote:

But, it's not the whole shoulder, it only moves a few fractions of an inch per working. Else we'd all have head separations after the second firing. However, the more you move the shoulder around (by over-sizing) the more material flows.

Before the Internet Hatcher advanced the shoulder forward by .060" thinking there is no way a chamber can have that much clearance and survive firing a round without a case head separation. I have fired 8mm57 ammo in an 8mm06 chamber with .127" clearance without stretching the case between the case head and the case body.

The 8mm shoulder became part of the case body and shoulder, it was not magic but the 8mm neck disappeared with part of the 06 shoulder. If that case only had one shoulder from beginning to end it took one heck of a ride.

I have a M1917 that has a chamber that has .016" clearance, the belief is when fired the case will stretch between the case head and case body, that does not happen, when fired the shoulder of the round becomes part of the case body and part of the shoulder becomes part of the new shoulder; and the neck become shorter.

The neck becomes shorter because that is the part of the case that lost brass to the shoulder.

F. Guffey

All of this brass travel resulted in short cases, that is when I started forming 280 Remington cases to fit the long chamber M1917 chamber. The 280 Remington case is .041" longer than the 30/06 case, cant miss.