Gentlemen,

here an answer for the initial question:
Anyone have or had a 6.5x57?

I have reloaded and shot on the range a Mauser 98 in 6,5x57.
The cases of RWS and Sellier&Bellot were not especially thick (in comparism to 7x57 cases).

The cartridge reloads easily, I developed loads for roe deer hunting from a "Hochsitz".
Range was expected to be below 100 meters and roe deer is a light-boned animal, so we tested Nosler 120grs Ballistic Tip and Hornady 129grs SST with Kemira N140.
The result was very good on roe deer/body shots and the Hornady 129grs SST, this was also the bullet which was most precise (tested with a 6power scope, so this remark has to be regarded with caution...).

If anyone is interested, I can provide data for US powders like IMR4320, IMR4350 and IMR4831.

best wishes for 2012!
Rolf