Re: 8x57mm cartridge
The 220 SGK was actually designed for use with the 8mm Rem Mag, so it may be a bit tough with the 8x57. Should still be usable, and it sounds like you've played with it a fair bit yourself. I've shot tons of the 200 SMKs in testing over the years, and it's a very easy combination to work with in an 8x57. That round, incidentally, was my stadard accuracy test cartridge for teh 8mm bore size. It was always like shooting a 308 with 168 grain bullets; load them up with any of wseveral sutiable powders, and they'd shoot tiny little knots all day long. Very easy bullet to work with.
Never had the chance to work with the 8x57 at extended ranges, but certianly never inteded to denigrate its capabilities. The performance of the schwere balle in the MG roles demonstrated that beyond all doubt, as did Matthias Hetzenauer. I say again, great cartridge and still a fine performer.