Help with false shoulder....

[eschafer]

I have 100 new virgin .338 win mag brass... bag of Winchester and bag of Hornady... both brands are short from case head to shoulder when compared to once fired from my rifle.... Win is shortest, approx 0.016-0.018" on average....

I've posted before regarding this brass and it was suggested to first create a false shoulder with a "tapered expander" of size approx .350", then, neck size back to .338 and allow case to headspace on shoulder for first shot.... (I understand this).

My question is: which brand "stem and tapered expander" do I purchase? My FL resizing die is a RCBS FL standard... One can see all sorts of different shaped expanders at Brownells, but I never know if the stem and threads are compatible with my RCBS die....A link to an appropriate "tapered expander"/ stem would be greatly appreciated... Still new to reloading, some of this is not yet second nature to me.. thanks in advance....

[catnthehat]

Have you actually tried loading and firing this brass and seeing what happens first before going through all the procedures of creating a false shoulder first?
Cat

[6MT]

Of course virgin brass will be shorter then fire formed brass. Fire them when you load them and they will "lengthen" to your chamber (ei: fire form).
After once fired, you resize however you like. I don't full length my brass. I bump the shoulder .0015" and neck size with a bushing die (for a bolt gun).

[260 Rem]

Why are you wanting to create a false shoulder? The only time I create false shoulders is when blowing the shoulder forward to make a new cartridge (6BR to 6 Dasher). The purpose of creating the false shoulder in that application is to insure the cartridge headspaces properly thus avoiding a potential case head separation (injury).
To answer your question, look at the Sinclair expander dies.
I just necked some 6.5 X 284 brass up to 30 cal using standard Hornady expander buttons.

[catnthehat]

Here's an idea - load up ten new brass and ten once fired .
Head to the range and shoot them all randomly at 200 yards with someone else loading the rifle so you can’t tell which one you are firing.
Pretty sure the results will show that you are trying to fix a problem that does not exist .
Cat

[qwert]

IMHO&E:
to minimize thinning of the case wall at the head junction, it is best to size all belted brass to head-space on the shoulder rather than the belt.

Fire-forming brass is best performed by forming a false shoulder before first firing.

A heavy lead boolit seated hard into the lands also works, but with less concentricity than forming a false shoulder.

For maximum case life before head separation, I suggest pulling factory loaded and forming a false shoulder before re-seating bullet and first firing and fire-forming.

Bill Leaper suggests oiling the outside of case and neck before firing to prevent initial case stretch at the wall to head junction.

I often use Hornady tear drop shaped expanders, but the longer taper Lee expanders are good (after cleanup smoothing and polish).
Hornady markets an expander rod # 390969 to use their expanders in RCBS dies.
I suspect that the Lee expanders could? be used in their universal de-prime die.

http://www.outdoorsmenforum.ca/printthread.php?t=354838
http://www.outdoorsmenforum.ca/printthread.php?t=330610

I use Redding Competition shell holder set (each SH is +.002” increment over standard height)
for repeatable partial sizing and shoulder bump without constant die height re-adjustment.

CBTD (case base to datum) length may (not always) be increased by partial FL sizing.

Good Luck, YMMV..

[eschafer]

""IMHO&E:
to minimize thinning of the case wall at the head junction, it is best to size all belted brass to head-space on the shoulder rather than the belt.

Fire-forming brass is best performed by forming a false shoulder before first firing.

A heavy lead boolit seated hard into the lands also works, but with less concentricity than forming a false shoulder.

For maximum case life before head separation, I suggest pulling factory loaded and forming a false shoulder before re-seating bullet and first firing and fire-forming.

Bill Leaper suggests oiling the outside of case and neck before firing to prevent initial case stretch at the wall to head junction.

I often use Hornady tear drop shaped expanders, but the longer taper Lee expanders are good (after cleanup smoothing and polish).
Hornady markets an expander rod # 390969 to use their expanders in RCBS dies.
I suspect that the Lee expanders could? be used in their universal de-prime die.

http://www.outdoorsmenforum.ca/printthread.php?t=354838
http://www.outdoorsmenforum.ca/printthread.php?t=330610

I use Redding Competition shell holder set (each SH is +.002” increment over standard height)
for repeatable partial sizing and shoulder bump without constant die height re-adjustment.

Good Luck, YMMV..""


Thank you... and I see it was you that suggested a false shoulder back then... However, I have not been able to find Hornady expander rod # 390969 anywhere on the net.... If I could find a listing for this rod and a tear dropped expander which works, I could be off and running...

Also, for the other members wondering why I want to create a false shoulder, the above explanation sums it up.. I want brass longevity and minimal stretch/thinning just above the belt.... Thanks to all respondents... Eric

[qwert]

Originally Posted by eschafer

Thank you... and I see it was you that suggested a false shoulder back then... However, I have not been able to find Hornady expander rod # 390969 anywhere on the net.... If I could find a listing for this rod and a tear dropped expander which works, I could be off and running...
snip

I suggest you phone Hornady direct.
I tried searching the net and their site, but could not find their expanders or # 390969 rod listed.
They mailed me RCBS adapter rods # 390969 for free after inquiry.

Good Luck, YMMV.

[260 Rem]

I do not reload any belted cartridges, but would assume that when the cartridge is fired it blows the shoulder forward and thereafter headspaces on the shoulder unless you tinker with the resizer die set up?

[qwert]

Originally Posted by 260 Rem

I do not reload any belted cartridges, but would assume that when the cartridge is fired it blows the shoulder forward and thereafter headspaces on the shoulder unless you tinker with the resizer die set up?

Excessive cartridge head-space will also cause wall thinning at the wall to head junction in non-belted cartridges.
The brass for the case lengthening comes from the lower case wall.

Good Luck, YMMV.

[260 Rem]

With the Dasher, the brass needed to reform the shoulder forward of close to 0.1” is from the neck. I doubt there is much thinning near the base...at least I have never had an issue with brass fired +20 times.
Now back to the belted case which I do not fully understand...it seems the case would “blow” forward and with springback, would leave about .001 - .002 headspace at the datum point on the shoulder? Presumably, that headspace should remain somewhat constant after repeated firings ...a least until the brass looses its ability to spring back?

[Dean2]

I load for many belted magnum rounds. You are trying to fix a problem that does not exist. For the first round the case will headspace on the belt. After that, if you only neck size (I pretty much neck size all of mt brass and keep it separated so it is always used in the same gun) or partial full size it will head space on the shoulder. Creating a "false Shoulder" will not stop the brass from flowing forward to expand the case, move the existing main shoulder forward, to fit your chamber, it just means the case stops on the false shoulder instead of the belt. This is actually likely to make brass flow worse rather than better and may bulge the area above the belt by having the belt stop further back in the chamber and having the web where the belt should be.

In 55 years and after wearing out a dozen 300 mag barrels plus a half dozen assorted other belted mag barrels I have NEVER lost a belted case to head separation. I can easily get 15 firings on a belted case unless I am running them real hot and then the primer pockets get loose after 5 or 6 firings. I do not anneal any brass so all cases that I have binned were for loose primers or neck cracking from work hardening.

[elkhunter11]

Originally Posted by Dean2

I load for many belted magnum rounds. You are trying to fix a problem that does not exist. For the first round the case will headspace on the belt. After that, if you only neck size (I pretty much neck size all of mt brass and keep it separated so it is always used in the same gun) or partial full size it will head space on the shoulder. Creating a "false Shoulder" will not stop the brass from flowing forward to expand the case, move the existing main shoulder forward, to fit your chamber, it just means the case stops on the false shoulder instead of the belt. This is actually likely to make brass flow worse rather than better and may bulge the area above the belt by having the belt stop further back in the chamber and having the web where the belt should be.

In 55 years and after wearing out a dozen 300 mag barrels plus a half dozen assorted other belted mag barrels I have NEVER lost a belted case to head separation. I can easily get 15 firings on a belted case unless I am running them real hot and then the primer pockets get loose after 5 or 6 firings. I do not anneal any brass so all cases that I have binned were for loose primers or neck cracking from work hardening.

Exactly, you are concerned about a non issue, just load the cases, fire them, then only bump back the shoulder the minimum amount to allow them to chamber easily.

[eschafer]

Thank you to all..... I'm considering all suggestions carefully.... Eric..

[qwert]

Originally Posted by 260 Rem

With the Dasher, the brass needed to reform the shoulder forward of close to 0.1” is from the neck. I doubt there is much thinning near the base...at least I have never had an issue with brass fired +20 times.
Now back to the belted case which I do not fully understand...it seems the case would “blow” forward and with springback, would leave about .001 - .002 headspace at the datum point on the shoulder? Presumably, that headspace should remain somewhat constant after repeated firings ...a least until the brass looses its ability to spring back?

We agree that fire-forming and full load firing moves brass.
Where it comes from depends a lot on case fit & position in chamber, firing pressure and impulse time, and brass hardness and grip on the chamber.
(I suspect that you (IMHO correctly) annealed the neck and shoulder for the Dasher before forming.)
It is easier to pull the brass (cause to yield) from the softer neck and shoulder, rather than the harder (= higher yield strength) lower wall & head junction, and can be observed by the shortened OA case length.
The forming of your shoulder was complete long before the still increasing pressure caused the soft neck and upper wall brass to solidly grip (and seal) the case to the chamber wall. The false shoulder kept the case head against the bolt face (and resisted the forward force of firing pin strike and primer ignition), so there was no brass stretched at the wall to head junction when the full firing pressure pushed the head back to the bolt.

Good Luck, YMMV.

[260 Rem]

I don’t, nor have I ever heard of annealing 6BR brass before reforming it in the Dasher chamber. I might anneal it after a dozen reloads but typically not necessary.
OP, Elk is right...don’t overthink it.

[Grizzly Adams]

Magnums headspace off the belt. what's the problem ?

Grizz

[obsessed1]

Originally Posted by qwert

IMHO&E:
to minimize thinning of the case wall at the head junction, it is best to size all belted brass to head-space on the shoulder rather than the belt.

Fire-forming brass is best performed by forming a false shoulder before first firing.

A heavy lead boolit seated hard into the lands also works, but with less concentricity than forming a false shoulder.

For maximum case life before head separation, I suggest pulling factory loaded and forming a false shoulder before re-seating bullet and first firing and fire-forming.

Bill Leaper suggests oiling the outside of case and neck before firing to prevent initial case stretch at the wall to head junction.

I often use Hornady tear drop shaped expanders, but the longer taper Lee expanders are good (after cleanup smoothing and polish).
Hornady markets an expander rod # 390969 to use their expanders in RCBS dies.
I suspect that the Lee expanders could? be used in their universal de-prime die.

http://www.outdoorsmenforum.ca/printthread.php?t=354838
http://www.outdoorsmenforum.ca/printthread.php?t=330610

I use Redding Competition shell holder set (each SH is +.002” increment over standard height)
for repeatable partial sizing and shoulder bump without constant die height re-adjustment.

CBTD (case base to datum) length may (not always) be increased by partial FL sizing.

Good Luck, YMMV..

I have been doing this for years for my belted 300. Definitely increases case life.

[Bushrat]

Originally Posted by Grizzly Adams

Magnums headspace off the belt. what's the problem ?

Grizz

Measure the belts on a few of those magnum cases, then measure a few different brands, the distance from the base to the top of the belt will generally vary quite a bit, I've seen as much as .020" variance. Then measure your chamber, the cut out for the belt is generally even bigger and deeper. Generally most belts on magnum brass are loose and not touching the chamber at all doing nothing but floating around having no effect on headspace.

[Pathfinder76]

Originally Posted by 260 Rem

I do not reload any belted cartridges, but would assume that when the cartridge is fired it blows the shoulder forward and thereafter headspaces on the shoulder unless you tinker with the resizer die set up?

Yes it does, but excessive headspace can create head separation. And yes this is a real problem and not uncommon with the 338.

How much headspace are we talking about OP?

[Pathfinder76]

OP, are you saying that you have between 16 and 18 thousandths head space?

[eschafer]

No...(because I'm only concerned about first firing)... And on first firing, it will headspace on the belt....

But, on first firing, case head to shoulder datum measurement will be 0.016"-0.018" shorter than my fired/ formed cases... I was understanding that to reduce case stretch near the belt (where case head separation occurs), a false shoulder for first firing is useful in controlling where and what is being stretched....

This inquiry is only about prepping new, virgin, short from base to shoulder datum brass, FOR FIRST FIRING ONLY..... Once case is formed, stretched and now representative of my chamber dimensions, I can then proceed with partial FL sizing, to minimally move back shoulder....

It seems many members feel the step is really not necessary.... and, many members feel it is helpful....

I will ponder the options... Thank you.....

[obsessed1]

I have not loaded for 338 but for my 300wm I use a lee die with a 338 expander in it to open up the neck then I run the case through another lee die set up to push the false shoulder back just far enough to give a tight chamber fit( not a crush fit) all subsequent resizing is done with a rcbs die to bump the shoulder back .002. Perhaps a 375 expander would work the same way for a 338

[Pathfinder76]

16 thou will certainly run the risk of case stretch that will alter the brass. I’d be fire forming with a false shoulder, but that’s just me.

[JD848]

Originally Posted by chuck

16 thou will certainly run the risk of case stretch that will alter the brass. I’d be fire forming with a false shoulder, but that’s just me.

x2 on that one.

[marky_mark]

Question?
Why would you be using 2 different brands of brass?
Would they not have different case capacities?
Wouldn’t that be a bigger issue than the false shoulder?

[Dean2]

For all you guys advocating the false shoulder approach, how many belted magnum cases have you had with case head separation? After how many reloads did this show up. Unless it was after the first firing, which likely indicates a headspace issue,, you have been FL sizing the cases far too much. Brass does not flow much if you aren't over sizing the cases. Like I said before, many thousands of reloads on belted mags and I have never had a single belted mag case show head separation.

[Pathfinder76]

Originally Posted by Dean2

For all you guys advocating the false shoulder approach, how many belted magnum cases have you had with case head separation? After how many reloads did this show up. Unless it was after the first firing, which likely indicates a headspace issue,, you have been FL sizing the cases far too much. Brass does not flow much if you aren't over sizing the cases. Like I said before, many thousands of reloads on belted mags and I have never had a single belted mag case show head separation.

I don’t have case head separation because I size my cases correctly.

Here is a simple test that the OP can do. Load a case and fire it. Then section the case lengthwise. Any stretch will be quickly evident. Now, if there is, you may be able to load them and be fine. But those cases are compromised. Not all belted magnum chambers are the same either so just because you haven’t seen issues doesn’t mean they don’t exist.

I would not be letting my cases stretch 16 thousandths of an inch. But could honestly care less if anyone else does. Fill your boots.

[Dean2]

Originally Posted by chuck

I don’t have case head separation because I size my cases correctly.

Here is a simple test that the OP can do. Load a case and fire it. Then section the case lengthwise. Any stretch will be quickly evident. Now, if there is, you may be able to load them and be fine. But those cases are compromised. Not all belted magnum chambers are the same either so just because you haven’t seen issues doesn’t mean they don’t exist.

I would not be letting my cases stretch 16 thousandths of an inch. But could honestly care less if anyone else does. Fill your boots.

So you are telling me you have never had to trim cases because they got too long? If you have ever trimmed cases then the brass stretched and a standard trim amount is 10 to 15 thou depending on the case.

[obsessed1]

I have never had a case separate because I size properly and discard before they get to a point of failure. I do however have a rcbs case measure tool that allows me to measure any area on a case. I have the info recorded some where but in 2006 when I got my first belted mag ( 300 wm) I read about this method for dealing with virgin brass so I decided to test the theory out. I measured and recorded case thickness right in front of the belt on 20 cases and used a sharpy to label them. 10 of them I left as is the other ten I created a false shoulder. I don't remember the amounts but all of the non false shouldered brass showed thinning in front of the belt were as only one of the false shoulder brass showed any thinning. That data led me to believe that the cases with false shoulders did expand and flow but it was over a larger percentage of the case body, but given space in front of the shoulder the simplest area of movement was all forward starting at the belt. Not a conclusive test by any means but it did proov e the worth of doing the step in my mind then..I have just continued since