Doner case to form into 8 X 57R/360

[Blackknight]

Anyone know how to make this conversion?

[skeettx]

https://www.thehighroad.org/index.php?threads/8x57r-360.442748/

[17nut]

360 Nitro
9.3x72R

Amongst others

[Firebird]

RWS 8x57 JRS (rimmed case) are available from Huntingtons (http://www.huntingtons.com/store/home.php?cat=275&sort=orderby&sort_direction=0&page=2), not cheap but then anything that can be formed to this case won't be inexpensive either.