Forming questions.

[std7mag]

Say someone was going to wildcat a cartridge based on a .444 Marlin, or a .45-70.

How does one form a bottle neck cartridge from a straight walled cartridge?

If going from the .45-70 and necking to say a 6.5mm would this have to be done in multiple steps?

How would you get the critical headspace dimension correct?

Thanks!!!

[tangolima]

I formed 7.7 Arisaka from .30-06. Not exactly the same thing but at least part of the principle should apply.

First cut the casing to approximate length, slightly longer of course. Hack saw, tubing cutter or whatever tools appropriate.

Lube with good lube and feed the casing to the new die. It could be pretty hard going, so go slow. I constantly back off the press ram, rotate the casing and go again.

Trim the casing to final length. Turn the neck. Anneal.

The headspace is adjusted by screwing down the new die in the press, same as normal full-length resizing.

In your case, .45" to 6.5mm is a big jump. An intermediate step is probably needed. Try find a .30 caliber die that has greater dimensions than your final die.

Hope it helps.

-TL

[44 AMP]

Necking down from 44 or 45 caliber to 26 caliber (6.5mm) should be done in multiple steps. Otherwise you are going to have a totally unacceptable number of cases collapse.

You can have custom dies made, or if you have a number of loading die sets in various calibers like I do (I have over 30 in cals from .22 to .45) you can use some of them as steps along the way.

You will need a custom die set for your wildcat, to do your final reloading steps.

Going from .45 down to .40, then 37, 35, 32,30, etc., till you get where you want. The exact amount you reduce the neck each time isn't critical, until you start getting cases that fail. When cases start buckling or collapsing, you are taking too big a reduction in one step. The brass you are using is often the deciding factor.

Also, don't forget the trimming. Squeeing down the neck will result in a length change as well. At some point you are going to be trimming, so figure that into your process as well.

Headspace is NOT the same as case dimensions in all cases. Used the way we normally do, headspace refers to the fit of ONE set of case dimension in the rifle chamber. Often this is the distance from the case head to a point on the shoulder (aka datum line) but not always.

for Rimmed cartridges (like the .444 & .45-70) headspace is the measurement of the RIM thickness (or more accurately, the space in the chamber between the bolt face and the edge of the chamber where the case rim fits.

You could make a wildcat 6.5x444 or .45-70 and the "headspace" will be exactly the same as the factory cartridge. The same headspace gauge would be used, and the measurement would be accurate, for both the wildcat 6.5 and the factory .45, because with a rimmed case, what you are measuring as headspace is the same for both.

[HiBC]

I neck virgin .458 brass down to .375 for my 375 Taylor.I get some case failures at one pass.I found a cheap,used set of Lee 416 Taylor dies fot an intermediate step.Works great.

Most every brass has been necked up down and sideways by someone.Many somewhat standard wildcats have been created.I know JD Jones has worked with the .444 case quite a bit.You might also look at the .405 Win case.

If you can find something semi-standard to suit you,outfits like Redding will likely have forming die sets that will not require full custom prices.Same with reamers and loading dies.

If you are looking for a straight walled rimmed case to neck down to 6.5,I would not overlook bottlenecks like the 30-40 Krag,.303 Brit,and 7.62x54R.

I used to go to a lot of trouble to make straight walled 40 cal cases out of 30-40 Krag,very similar to .405 Win.

I believe the Aussies are quite fond of a 6.5 /303 and the 6.5 Krag Ackley Improved has been done.IMO,a 6.5 /220 Swift might be an efficient cartridge if you have a shorter barrel length in mind

[old roper]

45-70 case has no shoulders so neck down your going to have to form some type of shoulders. It could be from shoulder like 300H&H to standard type found on modern case.

In The Handloader's Manual of Cartridge Conversions page 776 is case called 6.5x58R Krag-Jorgensen it's form from same case as the 45-70 (45 Basic). case length is 2.285" vs 2.105" for the 45-70.

There is also 6.5x57R Mauser formed from the 444 marlin case and has case body/shoulders/case neck same as the 6.5x58R and form dies were used.

Here place to look for dies

http://www.huntingtons.com/ref_rcbs_diespecial.pdf

The have both dies not sure if the 6.5x58R are same as Krag-Jorgersen.

Other problem is form dies necking down.

http://www.huntingtons.com/store/home.php?cat=580

Might be better to pick case that you can get form and reloading dies for then have reamer made.

Well good luck

[F. Guffey]

std7mag,

"Say someone was going to wildcat a cartridge based on a .444 Marlin, or a .45-70.

How does one form a bottle neck cartridge from a straight walled cartridge?

If going from the .45-70 and necking to say a 6.5mm would this have to be done in multiple steps?

How would you get the critical headspace dimension correct?"

Thanks!!!



I form 35 Winchester from 45-70 cases with a forming die, after forming the cases must be sized with a 35 Winchester full length sizing die. The difficult part, keeping up with the distance from the shoulder to the head of the case, a reloader should be able to keep up with the math. I keep up with the math by measuring the length of the chamber first (4 ways), As I form the case I understand the shoulder is not being bumped, my shoulders are formed meaning the shoulder on the formed case is new, it has nothing to do with the old shoulder (the old shoulder does not move), if the case had a shoulder it is erased, the old shoulder became something else.

Reloaders have head space gages, all kinds, I don’t, I have transfers, standards and verifying tools, I measure the length of the chamber (head space) from the datum/shoulder to the bolt face. I then transfer that measurement to my die. press and shell holder. I form the case length from the shoulder to the head of the case to off set the length of the chamber from the datum to the bolt face.

Going from .40” to 6.5mm is a leap without forming dies, I have 4 forming dies between .400” and 6.5mm/.264”. The angle of the shoulder is is critical when forming.

I have formed wildcat cases from 30/06 and 25/06 to 22/6 MM Remington Wildcats, the smith was having trouble with case head separation when fire forming. He was happy with loosing 5 cases out of 10, he could grasp the concept of forming before firing.

F. Guffey

[std7mag]

Thank you all for your replies!!

I was just using the .444 Marlin, and .45-70 as examples as they are straight walled. I wasn't actually planning on using one of those cartridges.

The casing I'm actually forming from is made as a straight wall, and must have the bottle neck formed onto it. So sayeth the casing manufacturer...

[F. Guffey]

“How would you get the critical headspace dimension correct?" “

I do not have an infatuation with ‘HEAD SPACE’, I do not find ‘it’ critical. All I am required to do is determine the length of the chamber from the shoulder/datum to the bolt face. I off set the length of the chamber with the length of the case from the shoulder/datum to the head of the case. When forming straight wall cases to cases with shoulders the reloader forming the cases can form cases that fit.

I form cases for a M1917 that has an additional .016” added to the length of the chamber from the shoulder to the bolt face, I form 280 Remington cases to 30/06 by adjusting the die off the shell holder .014”, I form first then fire. When I eject a case it is a once fired case.

effectuation: About head space, I could have an effectuation about head space.

F. Guffey