Resizing brass from one cartridge into another

[300magman]

I've seen people do incredible things with cases...imagine a 50bmg necked down to .224 for example.
But how is it done?

Specifically I wondering about how do reduce a cartridges length, imagine a 300WSM case with .3" removed from the center, otherwise exactly the same base, shoulder, neck etc. How would one do something like this for example?

If done properly, would it reduce the integrity of the case or cause thick/thin spots around the shoulder or neck?

[darkgael]

You are talking about "wildcats" or the practice of forming new cartridges by reforming existing cases.
There is also the common practice of making a current cartridge case from a similar but different cartridge case. For instance, you can make .30-30 cases from .375 Winchester cases simply by lubing them well and running them through a .30-30 sizing die.
There are a number of informative books about wildcats and custom case forming.
A basic source, not actually about the forming process, but a solid list of many common wildcats, is "Cartridges of the World".
Three basic books about custom cases:
Ken Howell's "Designing and Forming Custom Cartridges"
John Donnelly's "The Handloader's Manual of Cartridge Conversions.
George Nonte's "The Home Guide to Cartridge Conversions."
And there is P.O. Ackley's "Handbook for Shooter's and Reloaders".
Of course, making new cartridges does no good unless you have a gun chambered for them.
About the 300 WSM - that is fairly easy. You only have to move the shoulder back .3" and then trim the neck to the needed length. The resulting neck would probably be thicker, at least for part of its length as case walls thicken the closer one gets to the head. It might have to be reamed. You would need a die that would allow for that much movement. Then you'd need to chamber a rifle for the new and shorter case in order to use it.
Brass is a very "plastic" metal, especially in its annealed state. The same qualities that make it ideal for sealing a chamber against high pressure gas, allow it to be formed in dies under pressure.
Pete

[woods]

Necking down is not an easy project. The general consensus is that reducing the neck size more that ~.050" at a time is undoable as it will collapse the case.

I am presently trying methods for necking down a 375 Ruger case to 30 caliber. There are die manufacturers who will make custom dies for you but that is about $150.00 and $75.00 for the interim reducing dies. If you can find a die in another caliber that will work then it gets cheaper. For instance in my case, I am getting a 338RCM FL die as the interim forming die and then the 300RCM FL die for taking the neck down to the final dimensions.

There will be case neck thickness issues and you will probably have to get into outside neck turning and possibly inside neck reaming to fix the smaller ID neck.

It is easier to expand the neck with expanders but going from 50 caliber to 22 caliber would get very very technical and since it impossible for bullets to go much faster than somewhere around 5000 fps or so then you would have the antithesis of efficiency in that cartridge and no one makes a powder slow enough to even come close to loading for one. The barrel would probably last about 50 shots and the throat would be gone.

[darkgael]

The general consensus is that reducing the neck size more that ~.050" at a time is undoable as it will collapse the case.

I suppose that I'm picking an exception but that .375 to .30 conversion that I mentioned is just as easy as I wrote. One pass and you are done.
I acquired a box of .375 Win brass at a range once. I had no use for them as they were. The .375 case is basic brass for the .30-30.
Twenty tries, twenty conversions. No collapse. I'm sure that there are thinner -walled parent cases which require more staging but that one was easy or I was lucky.
Pete

[Scorch]

How do you neck down cartridges? Is that what you are asking? Well, you could:
* Run the case into a resizing die a similar-sized cartridge but vary the length by how far you screw the die in, or cut the die back for a shorter cartridge.
* Use a set of wildcat shoulder and neck forming dies. These are dies that form just the shoulder and necks. There are also modular dies for forming necks of a given caliber from a larger case, and dies for forming shoulders and body taper.
* If you have an idea for a wildcat that does not exist yet, you can make a drawing of the case and just about any reloading die manufacturer will make you dies, and a reamer can be had from Clymer or PTG.

Here's a primer on wildcatting.

[Sport45]

I don't think he's talking about necking down a case. He's asking about shortening one (setting the shoulder back). I do this frequently when making 7.7jap bras out of .30-06 brass. I just lube the '06 brass and run it in my 7.7jap die and then trim the excess neck that develops back to proper length for the 7.7jap. If the cases needed to be shortened much more than this it might be necessary to trim first so the brass doesn't hit the end of the die.

[Malamute]

I've made 308 cases from 30-06 cases just to see if it's feasable. I did maybe 20 cases. I first used a Forster case trimmer to shorten the case, it ended up cutting back to about the middle of the shoulder. Then lube the case and run it into the 308 sizer die. I think I went about 1/3 of the way in, backed it out, then another 1/3, then backed out, then all the way in. Made fine cases, tho the necks will need thinning some. I re-trimmed again after the forming to even them up, and deburred. The first case trimming was the biggest pain in the behind.

[Bart B.]

I've sized .300 Win. Mag. cases in a .30-.338 nWin. Mag. die setting their shoulders back about a tenth of an inch. This is the .30-.338 Keele or Long Neck. A very accurate cartidge.

[okie2]

Lee makes trim dies.
I make my 30 herrett out of 3030 cases just push them in and cut off ABOUT 3/8 OF AN INCH with a fine toothed hack saw and then trim in a trimer. EASY DOABLE Same can be done to move a shoulder back shorter.

[darkgael]

Sport: He is, at least in part, asking about necking down.

.imagine a 50bmg necked down to .224 for example.
But how is it done?

When you make the Jap case, do you have to ream the necks at all?

Pete

[Sport45]

This is what I was going on.

Specifically I wondering about how do reduce a cartridges length, imagine a 300WSM case with .3" removed from the center, otherwise exactly the same base, shoulder, neck etc. How would one do something like this for example?

I haven't needed to ream the necks of the .30-06 to 7.7Jap. My Arisaka's chamber is generous enough that ammo loaded with the resized cases drops right in.

Neck reaming probably would be necessary in the OP's example above. That's a lot of metal being moved from the shoulder to the neck when shortening a case by 0.300". As you allude, the neck would be pretty thick.

[F. Guffey]

300 MAGNUM, "Specifically I wondering about how do reduce a cartridges length"



No one measure the length of a case before forming and or after forming, they do not measure the thickness of the brass through the forming process, to lead to the confusion there are terms used like "move the shoulder forward" 'move the shoulder back" truth is neither happens, when forming a case the shoulder does not move, it is erased as in your example with the 224, when formed the shoulder becomes the neck, the shoulder is erased and part of the case becomes the shoulder, the shoulder did/does not move.



Then there is the problem with the term flow and stretch, to get thicker the case must be compressed, stretching will cause thinning, when forming the brass flows forward, when sized down through the shoulder of the forming die the diameter of the case is reduced, it is assumed the neck gets thicker because of this, consideration is never given to the potability the brass when neck down flows faster through the neck and as a results necking the case down lengthens the case. brass is thinnest at the neck and is gets progressively thicker toward the head of the case., by how much? Again no one measures,



When I full length size a case, the neck gets longer when I raise the ram , when I lower the ram and pull the neck sizer ball through the neck, the neck gets shorter.



7.7 Japanese cases were expensive and or not available, with a 308 Winchester forming die I formed 30/06 cases by adjusting the 308 forming die off the shell holder. 070 thousands, then formed the cases and cut the excess off with a hack saw before lowering the ram then used a full length sizer die, again by adjusting the sizer die off the shell holder with a feeler gage.



I full length sized 20 cases with out a gap, these cases were minimum length size cases, .005 shorter from the head of the case to to it's shoulder than the perfect chamber from the bolt fact to the shoulder of the chamber. Then I adjusted a gap of .005 between the shell holder and bottom of the die (ram up) and sized 20 more, these cases were go-gage size, .005 longer from the case head to their shoulder than the cases that were minimum length sized. I then adjusted the gap between the bottom of the die and top of the shell holder and sized 20 more cases, I labeled these cases no go-gage length cases, I kept 3 cases out of each 20 and mailed them to someone that had purchased a 7.7 rifle. He sent me a message, all of the minimum length cases were loaded and chambered without effort, he said the go-gage length cases chambered with slight resistance, then he said he had to full length size the no go-gage length cases because none of them would chamber, later I met him at the Dallas Market Hall Gun show, by that time he had at least 3 firings on the cases, he had other questions, I introduced him to other people he needed to become familiar with for second opinions.

When forming 30/06 cases to 7.62 NATO reaming the neck is not required, more times than not when forming 308 Winchester from 30/06 reaming the neck is required.

When forming 7.57 from 30/06 reaming the neck is not required but a few friends have chambered 7mm57 chambers to 280 remington thinking that is an ideal/simple conversiom, until they go to the range and fire the 280 Remington in the new chamber, seems the 280 Remington will remove all of the original chamber except part of the neck, when fired the cases are extracted with a neck with two diameters, the 7mm57 chamber is larger in diameter in the neck than the 280 Remington.

F. Guffey

[F. Guffey]

possibility...

Sorry about that,

F. Guffey

[F. Guffey]

then I formed 30/06 cases down to 25/06 then to 6mm Remington (243), then down to 222, as the shoulder was being formed and the brass flowed through the die past the shoulder the brass had a difficult time making the turn on the inside, this caused the brass to wad up (form a do-nut) at the shoulder/neck juncture. I reamed the neck to remove the 'do-nut' I could have used 25/06 or 7mm57 cases, but the cases were not going to be used to load and fire, they were going to be used to determine the effect the chamber would have on a when fired.

Had the cases been fired I would expect the neck to seperate from the shoulder when fired.

F. Guffey