Thread: Making Sizer / Reloading dies

I wanted to have a sizer die / case forming die for one of my vintage rifles so I could run a Nitro for Black load in it.

Obsolete Caliber dies are available for the 450 no1 Express BPE from Australia but $600 Inc freight
So time to make one

I made a die body from 416 SS and threaded 1 1/4" for the big RCBS press i do most of my case forming on.

I made a chamber cast of my 450 no1 Express.
This gave me the sizes I wanted less about a thou for my die.
I bored through the entire die blank to the neck diameter.
And then pre bored out most of the shoulder and taper to make it easier on the reamer



Then I made a 4 flute die reamer with the neck as a solid pilot.
I fluted and put the primary relief angles on in the dividing head on the milling machine.
I put the secondary relief on by hand with a fine file but not touching the last fraction of the cutting edge.
Hardened the reamer but didn't bother tempering it because it's a one use reamer really.
Then I lightly sharpened the final cutting edge by hand with a fine Indian stone.

Used it just like a usual chamber reamer and plenty of Reaming oil.
It cut very nicely


I cut the die a little deep and formed a new case from a donor virgin 470 nitro case suitably shortened and annealed
Tried that case in my chamber and it was a fraction long for my block closing behind it.
The smoke shows that the shoulder is too far forward



So I shortened the die body by the amount the case was protruding by and tried again.
Case chambers perfectly with die body hard down on shell holder



My hope is that this dies being based on my actual chamber will be much kinder to the brass
The British 450s varied a lot in actual chambers and the modern dies are likely to over work the brass

I'm happy with my 6 hours of work / learnings



And next time I do one it will likely only take 2/3 rds of the time this one took