30-30 is easier to find probably cheaper and long enough. Same work to the case head and base, not much difference on the neck.

Just a choice.

I've built 2 rifles and shot this caliber in matches, for 20 years and have made about 100 cases.

30/30 is best to start with, they have a ~.400 shoulder and the neck is about the right size to begin with.

The original case heads vary a little but, are basically .400 @ .20 ahead of the base. Drill a 25/64 hole, about 2" deep, in a 1" piece of CRS. Polish out the first 1/2" to no larger than .398, then add a radius of ~1/8R to it. polish it very well. Shorten you cases to 1 7/8" and lube the case with Imperial wax or Hornaday case lube. Then size the case as far and hard as you can, on to the case head.

In the lathe, I cut a .050 deep recess at what ever the rim size is on the 30/30 brass (close fit)  and I turn a piece of aluminum, larger than the case, to what ever diameter the case mouth is, with a center hole in it. I put the center hole in the lathe center and push the inside of the case head against the recessed hole. That acts like a clutch and holds it while it's turning and turn the head down to .400. The reason i size the body smaller is to have clearance so the tool doesn't touch the case body.

Then you run it into your sizing die to form to your chamber. I then add about 8 gr of a fast powder about the speed of Unique, fill the case to the top, with CoW or corn meal, top it off with bullet lube and fire form. Then trim to .010 shorter than your chamber, usually about 1.875 - 1.88. 

The cases last a long time. I think I still have some that I made in 1987.

I've got breech seated loading data, for 180 - 190 gr bullets, if you need it.

Exactly what I was looking for. Thank you for taking the time to type out your procedure. 

My dies are on order from CH tool unfortunately they are six plus months out at best. Frustrating to say the least but good things come to those that wait , right?!

I had the box checked to be notified of a reply but it must not be work so sorry for the delay in getting back.

Thank again!

If you’re going to the trouble of making your own brass. Get a good measurement of your chamber. My Maynard measures close to .409” at the case head so I size my brass .406-7”.

For a die I bought the cheapest 32-40 die I could find, Lee I’m pretty sure. Cut it off so base diameter was what I wanted and radiuses the edge.
Size the brass just past the 200 line so I’m not cutting into the case head when I turn the base to size on the lathe.

Depending on your bullet size, you  probably need to neck down some, or use another shorter 32-40 die. That just gets the neck and a bit below.m
Then fire form