Gentlemen,

thank you for your support!

@Daryl: Thank you!
I do also only neck-sizing and was familiar about this process, but you gave some more and very interesting information about this topic!
I will form the cases now not (as I intended first) as opening up 8x57 cases, but enlarge them completely and size back to a good fit.

@lancaster:
The rifle in question was yesterday reserved, I decided that I have a desperate need for it
:-)

best regards
Rolf