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Oh I forgot 8x58R is made from 45-70

That's an easy one to do

Friwi I decided to try the 45 Silhouette case
Formed one from 45-70 brass
Shortened to 1 1/2"
Sized in shortened for
There was a small base doughnut to remove from the base

Case is basically...

33 Winchester sure fills a gap between 30 cal and 38 nicely

And any decent wildcats based on those cases also.
Especially is an existing reamer can be used in conjunction with a smaller or larger pilot to make an exotic chamber.

But bearing in mind that...

There are lots of very nice British cartridges I would love to build or rebuild rifles in.
But going British is a real struggle because
1- Random bore and groove sizes
2- Seriously expensive...