Self-made reloading dies

[rysiora]

Hello! I'm thinking about making reloading dies on my own, in order to create custom wildcat cartridge. I'm going to CNC machine them

from steel and then harden it.
As case after leaving the die will be always a little bigger than inside diameter of the die, it must be JUST A BIT smaller to size the

brass as it should.
The thing I don't know is how to calculate the inner diameter of the die, so the resulting size of the catridge will be as it should.
Thanks in advance for help.

 

[tango2echo]

At one time RCBS would cut custom dies for about 4X the cost of normal dies. I do not know if this is still true. Leave die tooling to the pros. A local gunsmith may also be able to help you.

T2E

 

[rysiora]

Thanks, but I'm gonna to make it on my own. It isn't that hard to make on CNC. Just need to know how to design the die so it will size cases to proper diameter.

I'm going to make not just one set of the dies. Possibly I'll even have to make few variations during designing the wildcat. It's not just BAM, and the first design is the final one. It would get really expensive that way, especially I do have the stuff needed to make it on my own. But I'll think about letting the final die set to be made by pros though.

 

[OurSafeHome.net]

Go for it!

Keep us posted.

 

[dmazur]

From Hornady's latest catalog -

...Our custom-manufactured dies are made on precision CNC machines, that produce an exacting die to extremely tight tolerances. All we need is a chamber cast, three fired cases and/or a chamber reamer drawing...Expander balls, shell holders, shell plates, trimmer pilots, bullet seating stems and alignment sleeves can be made to fit any bullet of any profile...

Depending on case length, prices for a two-die set range from $145 to $345, in either full-length or neck size configurations. Accessories like expanders, shell holders, etc. are additional, of course.

As you are going to have to chamber a rifle for your wildcat, there's the chamber reamer to consider as well.

As far as the dimensions of the dies, why not measure an existing die set to get the dimensions of the neck and expander?

 

[loadedround]

If you do not, or can not ultra finely polish the inside of your custom made sizer die, no amount of case lube will ever get that stuck case out of your die. Just food for thought.

 

[lordgroom]

For one, I am very interested in the results. This is far beyond my skill set but don't be discouraged. Please keep us posted.

 

[fguffey]

Traditional thinking, dies and chambers are 'finished' with a reamer, I would suggest reading the Machinery's Handbook section pertaining to reamers first then locate the equipment required for tool grinding.

http://lautard.com/books-ge.htm

http://www.lautard.com/

http://castboolits.gunloads.com/showthread.php?t=21653

Then there is the non traditional thinking when making dies, the man was a machinist, had the machinery and tons of metal with lots of time, though labor intensive he made an adjustable sizer die that outclassed my feeler gage.

F. Guffey

 

[jmorris]

The thing I don't know is how to calculate the inner diameter of the die

How about measuring the difference between a non wildcat sized piece of brass and die.

 

[ranger335v]

"The thing I don't know is how to calculate the inner diameter of the die, so the resulting size of the catridge will be as it should."

Since you have the machinery to do it, make a trial die and try it, don't bother to harden it (surface hardening is only for wear resistance). From that, see how much springback you get and work from there. For sure, few, if any, of us can provide that kind of info with any degree of certainty.

A highly polished die wall is not required to extract a sized case but a reasonably smooth (not deeply scored) surface is. Actually, a mat surface in a sizer is usually better, that holds case lube in place much better than a mirror surface can possibly do.

 

[Sam1911]

As you are going to have to chamber a rifle for your wildcat, there's the chamber reamer to consider as well.

Curious about that as well. What kind of goals are you setting for your new cartridge? Obviously you're not just making brass and loading it up. At some point, a cartridge needs to find it's way into a gun!

You'll need to chamber a test barrel in your new cartridge dimensions, mount it in some kind of receiver, and run test firings to see if you've achieved the velocity and accuracy goals you've set.

What's your plan for that? How long do you expect your experiaments to take before you have a satisfactory new cartridge and a gun to shoot it out of?

By the way, please don't get discouraged when you find out that practically every combination of bullet diameter, case length, case volume, head size, case taper, neck length, shoulder angle, etc. has already been tried by someone. You still can produce something useful and fun, if not actually unique.

-Sam

 

[jmorris]

I assume it’s going to be a bolt gun, just find a neck size die in the caliber you are using and call it a day. The most you might have to do is bore it larger or change the shoulder angle.

 

[rcmodel]

Chambers & sizing dies are cut using roughing & finish chamber reamers.

I do not believe you can deep hole machine & finish a sizing die on a CNC machine.
You might use a CNC machine to grind the chamber reamers though.

See this about wildcats & sizing die reamers.

http://www.clymertool.com/wildcat/index.html

rc

 

[rysiora]

Thank you all for your advices!
I have a request: could anyone measure a .38 Special sizing die inner diameter and post it?
It would be a useful reference for me and unfortunately, actually I don't have any .38 die at hand.

 

[Ol` Joe]

Call these guys and ask you questions, they sell die blanks and finished dies.
http://www.z-hat.com/catalog/search.php?submit=submit&categories=Reloading&subcategories=Dies

 

[shaggy430]

Please post some pics when you are done. I'd like to see.

 

[Jim Watson]

Standard chambers and dies are cut with reamers.
But I note that custom bullet mould makers bore them instead of cherry cut.
If your wildcat is on a short case that might be possible for your barrel and dies.

Caveat, I am not a gunsmith or machinist.